Journal articles on the topic 'Zirconium in rutile'
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PAVLIUK, O. V., and V. M. PAVLIUK. "Rutile From the Zelenyi Yar Titanium-Zirconium Placer and Its Possible Primary Sources." Mineralogical Journal 44, no. 1 (2022): 16–31. http://dx.doi.org/10.15407/mineraljournal.44.01.016.
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Rutile of the Neogene-aged Zelenyi Yar titanium-zirconium placer was studied. The average size of the rutile grains is 0.25 mm that are elliptical, rounded, short-prismatic, isometric, and elongated-prismatic crystals in shape. On the surface of the crystals, elements of physical abrasion of varying degrees, as well as chemical dissolution, are observed. The color of the rutile crystals ranges from black to yellow with black and brown being the most common. A relationship between the concentration of various impurity elements and their variations with the color of the crystals is present. The highest average content of impurity elements is recorded in green rutiles and the lowest in light brown crystals. About 61% of the rutiles contain V2O5 (30% of all crystals; average content 1.28%), Nb2O5 (25%; 1.38%), FeO (24%; 1.10%), WO3 (9%; 0.91%), ZrO2 (9%; 0.85%), Al2O3 (2%; 0.70%), Cr2O3 (5%; 0.60%), SiO2 (7%; 0.57%). The temperature of primary rutile crystallization was calculated using Zr-in-rutile thermometry and corresponds to granulite and eclogite metamorphic conditions. Cluster analysis of 284 microprobe analyses of rutile allows at least five groups of crystals to be identified. According to the chemical composition of various rutiles, it can be concluded that they originated from metapelitic rocks, enderbites, and eclogite-like rocks located in the Dniester-Bug megablock of the Ukrainian Shield.
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Kohn, Matthew J. "A refined zirconium-in-rutile thermometer." American Mineralogist 105, no. 6 (June 1, 2020): 963–71. http://dx.doi.org/10.2138/am-2020-7091.
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Abstract The zirconium-in-rutile thermometer enjoys widespread use, but confidence in its accuracy is limited because experiments were conducted at higher temperatures than many rutile-bearing rocks and calibration uncertainties have not been quantitatively assessed. Refined calibrations were developed using bootstrap regression to minimize residuals in the natural logarithm of the equilibrium constant, based on experiments only (n = 32) and on a combined compilation of experiments and natural data (n = 94, total). Rearranging the regression to solve for T, and expressing Zr concentration (C) in parts per million (μg/g), the calibrations in the α-quartz stability field are: Experimental data set: T ( C ∘ ) = 68740 + 0 . 441 · P ( bars ) - 0 . 114 · C ( ppm ) 129 . 76 - R · ln [ C ( ppm ) ] - 273 . 15 . Combined data set: T ( C ∘ ) = 71360 + 0 . 378 · P ( bars ) - 0 . 130 · C ( ppm ) 130 . 66 - R · ln [ C ( ppm ) ] - 273 . 1 . Thermodynamics of the quartz-coesite transition as applied to the calibration for α-quartz yields calibrations for the coesite stability field: Experimental data set T ( C ∘ ) = 71290 + 0 . 310 · P ( bars ) - 0 . 114 · C ( ppm ) 128 . 76 - R · ln [ C ( ppm ) ] - 273 . 15 . Combined data set: T ( C ∘ ) = 73910 + 0 . 247 · P ( bars ) - 0 . 130 · C ( ppm ) 129 . 65 - R · ln [ C ( ppm ) ] - 273 . 15. Propagated temperature uncertainties are ±20–30 °C (2σ) for the experimental data set calibration, and ±10–15 °C (2σ) for the combined data set. Compared to previous experimental calibrations, the refined thermometer predicts temperatures up to 40 °C lower for T ≤ 550 °C, and systematically higher temperatures for T > 800 °C. With careful attention to distributions of Zr in rutile grains, precisions of ±5 °C and accuracies ~±15 °C may be possible, although a poor understanding of how to select compositions for thermometry will typically lead to larger uncertainties. The ZiR calibration promises continued high-precision and accurate thermometry, and possibly improved thermodynamic properties, but the sources of compositional variability in rutile warrant further scrutiny.
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Taylor-Jones, K., and R. Powell. "Interpreting zirconium-in-rutile thermometric results." Journal of Metamorphic Geology 33, no. 2 (December 5, 2014): 115–22. http://dx.doi.org/10.1111/jmg.12109.
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Shafei, Gamal M. S. El, and Christine A. Philip. "Solid Acids from Persulphated and Perchlorated Physical Mixtures of Zirconium and Titanium Hydroxides." Adsorption Science & Technology 20, no. 10 (December 2002): 977–93. http://dx.doi.org/10.1260/026361702321705267.
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Calcination at 650°C of a physical mixture of zirconium and titanium hydroxides led to the formation of the corresponding oxides, monoclinic zirconia and anatase. The adsorption of perchlorate or persulphate anions (as 0.05, 0.1, 0.2 or 0.4 M aqueous solutions) before calcination did not inhibit crystallization; however, perchlorate anions activated the formation of rutile in addition to the predominant anatase phase. Indeed, the adsorption of perchlorated anions prior to calcination allowed the thermodynamically less stable tetragonal phase of zirconia to be detected in addition to monoclinic zirconia at ambient temperature. In contrast, the adsorption of persulphate anions before calcination stabilized the tetragonal phase with no rutile phase being detected in this case. Infrared spectroscopy showed that adsorbed S2O82– anions were held more strongly by the solid than ClO4− anions which tended to decompose when the solid was calcined. The acidities of the solid acids produced because of S2O82– or ClO4−anion adsorption were studied via the adsorption of pyridine (pKa = 5.3) from cyclohexane solution. The amounts and strengths of the acid sites formed during persulphate treatment were higher than those resulting from perchlorate adsorption. The strength of the acid sites formed on samples calcined before loading with S2O82– or ClO4− anions showed no significant differences. Variations detected in the structural aspects arising from S2O82– or ClO4− anion adsorption were reflected in the texture as assessed by nitrogen adsorption at −196°C.
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TOMKINS, H. S., R. POWELL, and D. J. Ellis. "The pressure dependence of the zirconium-in-rutile thermometer." Journal of Metamorphic Geology 25, no. 6 (August 2007): 703–13. http://dx.doi.org/10.1111/j.1525-1314.2007.00724.x.
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Jaroenworaluck, Angkhana, Weeraw Sunsaneeyametha, and Ron Stevens. "Surface Characteristics of Zirconia-Coated TiO2 and its Phase Transformation." Key Engineering Materials 334-335 (March 2007): 1101–4. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.1101.
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Recently, zirconia has been considered as a suitable material for surface coating nanosized TiO2 for use as an electrode in a solar cell application. In this study, the TiO2 (P-25) coated ZrO2 was synthesized from P-25 TiO2 and coated with zirconium n-propoxide in the range of 2.5-50 wt.%. The surface of the TiO2 coated with ZrO2 were examined by X-ray diffraction (XRD) analysis, high resolution transmission electron microscope (HRTEM), which showed zirconia could coat onto the P-25 TiO2 surface. Any excess of zirconia has been deposited as separated particles. Peaks for tetragonal zirconia were observed from the XRD patterns in zirconia-coated P-25 containing more than 20 wt. % of zirconia after calcinations at 500 °C, 800 °C and 1300 °C. In addition, peaks of anatase could be observed from XRD patterns of the samples after calcination at 1300°C. The results show that coating zirconia onto the TiO2 grain surfaces may act to retard the phase transformation from anatase to rutile.
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Garcia, Hiana Muniz, Eduardo Felipe de Carli, Natali Amarante da Cruz, Jusinei Meireles Stropa, Lis Regiane Vizolli Favarin, Amilcar Muchulek Junior, Lincoln Carlos Silva de Oliveira, and Alberto Adriano Cavalheiro. "Study of the Zirconium and Silicon Homovalent Dopants Insertion on the Structure and Bandgap Energy of Titanium Dioxide Powders." Materials Science Forum 930 (September 2018): 67–72. http://dx.doi.org/10.4028/www.scientific.net/msf.930.67.
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The reconstructive transformation occurring during the anatase-to-rutile phase transition can be observed through adequate techniques such as Thermal Analyses and Z-ray diffractometry followed by structural refinement. The typical photonic properties of titanium dioxide photocatalysts depend on the anatase structure and how the modifiers can provide their performance enhancement. In the present work, we investigate the structural effects caused by the simultaneous homovalent modification on the anatase structure in order to understand the mechanisms of the anatase-to-rutile phase transition in terms of the atomic coordinates and the lattice parameters. The refined structures along the calcination temperature from 500 to 900 oC suggest the oxygen bonds are strongly affected in unmodified anatase in order to destroy and rebuilt the crystal structure and lead to the rutile phase formation above 700 oC, unless some modifier pairs stabilize them.
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Lazarević, Z. Ž., N. Ž. Romčević, M. J. Romčević, and B. D. Stojanović. "Raman Spectra of Bismuth Titanate Ceramics." Materials Science Forum 555 (September 2007): 243–47. http://dx.doi.org/10.4028/www.scientific.net/msf.555.243.
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Bismuth titanate is a typical layer-structured ferroelectric material and belongs to the Aurivilius type-structure compounds family. A bismuth titanate ceramic material could be obtained by mechanically activated synthesis after thermal treatment at a temperature slightly lower than in conventional solid-state reaction. In this case bismuth titanate was prepared through mechanochemical synthesis starting from bismuth oxide and titanium oxide in rutile form. The mixture of oxides was milled in a zirconium oxide jar in a planetary ball-mill in intervals from 1 to 12 hours. The ratio of powders to zirconium oxide balls during milling was 1:20. Bismuth titanate was formed after 1 h. The Raman spectroscopy analysis was performed.
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Sapiee, Aqilah, Yusoff M. S. Meor, and E. M. Mahdi. "Study on Indoor Nitrous Oxide Gas Neutralization by Using Anatase and Rutile Nanotitania." Advanced Materials Research 925 (April 2014): 210–14. http://dx.doi.org/10.4028/www.scientific.net/amr.925.210.
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Nitrous oxide is generally emitted from industry through fossil fuel combustion thus giving adverse effect to human health and environments. Catalytic converter is the common method used to neutralize this hazardous gas but the high cost of precious metals had limited its application. Nanotitania could neutralize nitrous oxide by the photocatalytic phenomenon and the material is effective as it has small band gap energy and large surface area. In this study, we produced both anatase and rutile crystalline phase nanotitania from a local titanium mineral as the starting material. A significant improvement to the properties of our nanotitania is due to the present of naturally doped neodymium and zirconium ions that are present in the titanium mineral. This make the band gaps for both anatase and rutile to be smaller and effective in photocatalytic process. Three different nanotitania formulations, pure anatase, pure rutile and mixed rutile and anatase phases, were tried in the study and the results showed that all these three formulations were able to neutralize the nitrous oxide within a very short duration. Comparative study was then performed with a blank sample and the result shows there is still significant amount of nitrous oxide present after the 2 hours run.
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Chaikovski, I. I., E. V. Chaikovskaya, O. V. Korotchenkova, E. P. Chirkova, and T. A. Utkina. "Authigenic minerals of titanium and zirconium of the Verkhnekamskoye salt deposit." Геохимия 64, no. 2 (March 15, 2019): 182–94. http://dx.doi.org/10.31857/s0016-7525642182-194.
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Newly formed titanium oxides and zircons have been identified in the salt and suprasalt of the Verkhnekamskoye Salt Deposit. These features have been associated with the hydrolysis of clay material and the release of colloidal titanium and zirconium hydroxide during diagenesis, catagenesis, and hypergenesis. This is made possible by sulfate reduction and the acidic environment, which are caused by the radiation–oxidation of Fe2+ from sylvite and carnallite. Anatase is formed both in the suprasalt and salt measures and, only in the lower part of the salt measures, in the rutile. Such a distribution can be associated both with an increase in the degree of catagenetic transformation of salt rocks with depth and with the composition of coexisting sulfate or chloride brines. A typical form of anatase crystals is pinacoid, but this is replaced by a dipyramidal structure in the carnallite zone, which is the location of the most acidic brine. Three types of twins were recorded for rutile, the formation of which is attributable to the growth of a dehydrated colloid of titanium hydroxide on a finely dispersed aggregate. The impurities V, Cr, and Zr (Al, Si, and Fe) established in the titanium oxides reflect the geochemical specialization of the aluminosilicate terrigenous material sources.
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Bahranowski, Krzysztof, Agnieszka Klimek, Adam Gaweł, Katarzyna Górniak, Alicja Michalik, and Ewa Serwicka-Bahranowska. "Structural Transformations of Hydrolysates Obtained from Ti-, Zr-, and Ti, Zr-Solutions Used for Clay Pillaring: Towards Understanding of the Mixed Pillars Nature." Materials 12, no. 1 (December 24, 2018): 44. http://dx.doi.org/10.3390/ma12010044.
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Structural characteristics of hydrolysates formed from the aqueous Ti-, Zr-, and Ti, Zr-pillaring solutions prepared from inorganic precursors (TiCl4 and ZrOCl2), was investigated and compared with that of precipitates obtained from the same solutions after a slight alkalization of pH to the values reported for the conditions of clay pillaring. The materials were recovered by lyophilization and subsequently subjected to calcination at 500, 800 and 1000 °C. Of special interest was the effect of pH on the possible formation of mixed Ti, Zr-oxide species. Powder X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope/energy dispersive spectrometer (SEM/EDS) analysis showed that even a relatively moderate alteration of pH in Ti-, Zr-, or Ti, Zr-precursor solutions caused substantial changes in the outcome of hydrolytic transformations, manifested by different phase and/or chemical composition of the resulting hydrolysates. Analysis of thermal evolution of hydrolysates showed that alkalization facilitated the transformation of anatase into rutile in materials obtained from Ti-pillaring solution, but retarded tetragonal to monoclinic zirconia conversion in samples derived from Zr-pillaring agent. The most striking effect was observed for the mixed Ti, Zr-pillaring solution, where an increase of pH enabled the formation of zirconium titanate as the only crystalline phase, rather than a multiphase mixture of anatase, monoclinic zirconia and zirconium titanate obtained from the more acidic precursor. The finding supports the model of mixed Ti-O-Zr network in props generated in Ti, Zr-pillared montmorillonites.
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Gleń, Marta, and Barbara Grzmil. "Photostability and optical properties of modified titanium dioxide." Pure and Applied Chemistry 84, no. 12 (October 12, 2012): 2531–47. http://dx.doi.org/10.1351/pac-con-12-01-09.
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The influence of different modifiers, P2O5, K2O, Al2O3, SiO2, CeO2, and ZrO2, on the optical properties and photostability of rutile titanium dioxide was studied. The research was aimed at obtaining pigmentary rutile titanium dioxide with the enhanced photostability. The optical properties such as brightness, white tone, and gray tone were improved when titanium dioxide samples were modified with zirconium instead of cerium. Titanium dioxide products modified additionally with Al2O3 displayed improved optical properties by comparison with appropriate titanium dioxide products lacking introduced aluminum. In comparison with unmodified material (∆E* = 21.8), a considerable increase of the photostability of modified titanium dioxide was observed. The lowest photoactivity, in the range of ∆E* = 0.96–2.45, was measured for the TiO2-PKAlSiCe series. A selective leaching method and X-ray diffraction (XRD) analysis were used to determine the distribution of modifiers in titanium dioxide materials. It was concluded that the differences in both photoactivity and optical properties of modified titanium dioxide depend on its phase composition.
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Haque, M. M., M. Shamsuzzaman, Muhammad Borhan Uddin, Abu Zafor Mohammad Salahuddin, and Ruhul A. Khan. "Fabrication and Characterization of Shielding Properties of Heavy Mineral Reinforced Polymer Composite Materials for Radiation Protection." European Journal of Engineering Research and Science 4, no. 3 (March 4, 2019): 15–20. http://dx.doi.org/10.24018/ejers.2019.4.3.1132.
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Heavy mineral and unsaturated polyester resin (UPR) based composite blocks were prepared for potential shielding of ionizing radiations. Locally available heavy minerals with Ilmenite, Magnetite, Garnet, Rutile, Zirconium contents were used to fabricate the composite blocks for the gamma photons with energies 0.662 MeV - 1.25 MeV. The shielding capacity was evaluated in terms of Half Value Layer (HVL), Tenth Value Layer (TVL), Sixteenth Value Layer (SVL), Linear attenuation coefficient, Mass attenuation coefficient, and reduced % of radiation intensity. The Ilmenite composite exhibits relatively good attenuation performance in the case of 0.662 MeV photons of Cs-137. On the other hand, Zirconium composite demonstrates relatively good attenuation capacity in the case of 1.25 MeV photons of Co-60 in comparison to the ordinary concrete block. The goal of this work is to explore some novel materials to be effectively used as gamma shielding options in radiation facilities at minimal cost.
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Haque, M. M., M. Shamsuzzaman, Muhammad Borhan Uddin, Abu Zafor Mohammad Salahuddin, and Ruhul A. Khan. "Fabrication and Characterization of Shielding Properties of Heavy Mineral Reinforced Polymer Composite Materials for Radiation Protection." European Journal of Engineering and Technology Research 4, no. 3 (March 4, 2019): 15–20. http://dx.doi.org/10.24018/ejeng.2019.4.3.1132.
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Heavy mineral and unsaturated polyester resin (UPR) based composite blocks were prepared for potential shielding of ionizing radiations. Locally available heavy minerals with Ilmenite, Magnetite, Garnet, Rutile, Zirconium contents were used to fabricate the composite blocks for the gamma photons with energies 0.662 MeV - 1.25 MeV. The shielding capacity was evaluated in terms of Half Value Layer (HVL), Tenth Value Layer (TVL), Sixteenth Value Layer (SVL), Linear attenuation coefficient, Mass attenuation coefficient, and reduced % of radiation intensity. The Ilmenite composite exhibits relatively good attenuation performance in the case of 0.662 MeV photons of Cs-137. On the other hand, Zirconium composite demonstrates relatively good attenuation capacity in the case of 1.25 MeV photons of Co-60 in comparison to the ordinary concrete block. The goal of this work is to explore some novel materials to be effectively used as gamma shielding options in radiation facilities at minimal cost.
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Blackburn, Terrence, Nobumichi Shimizu, Samuel A. Bowring, Blair Schoene, and Kevin H. Mahan. "Zirconium in rutile speedometry: New constraints on lower crustal cooling rates and residence temperatures." Earth and Planetary Science Letters 317-318 (February 2012): 231–40. http://dx.doi.org/10.1016/j.epsl.2011.11.012.
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Chittleborough, D. J., M. S. Tejan-Kella, and R. W. Fitzpatrick. "Genesis of podzols on coastal dunes in southern Queensland. V. Chemistry and mineralogy of the non-opaque heavy mineral fraction." Soil Research 36, no. 4 (1998): 699. http://dx.doi.org/10.1071/s97041.
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Eight podzols on coastal dunes from the Cooloola chronosequence, and an associated pedon from North Stradbroke Island (Amity), were studied to establish (i) the degree of homogeneity of the parent material between and within profiles, (ii) the extent of heavy mineral weathering, and (iii) whether the parent sediments of each pedon had a common proximate source. The pedons are Quartzipsamments and Troporthods with ages ranging from Holocene to Pleistocene. On the basis of ratios zircon : rutile, zirconium : titanium, and non-magnetic : very magnetic heavy minerals in the fine sand fraction (53–125 µm), we concluded that the parent materials of the Cooloola pedons were mineralogically similar. By using zirconium in the non magnetic heavy mineral fraction as an index for zircon, it is evident that there has been considerable pedogenetic weathering of the heavy mineral fraction. There is a statistically insignificant difference in hafnium concentrations of zircons which implies that parent sediments of the soils at Cooloola and North Stradbroke Island were derived from a common immediate source.
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Ganzha, О. A., Yu V. Kroshko, and H. O. Kuzmanenko. "ORE-BEARING OF THE LIVOBEREZHNY ZIRCON-RUTILE-ILMENITE PLACER DISTRICT." Geological Journal, no. 4 (December 28, 2022): 83–100. http://dx.doi.org/10.30836/igs.1025-6814.2022.4.255682.
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The relevance of the presented publication is due to the need to highlight the current state of zirconium-titanium specialization objects, the need to modernize and unify geological information, due to the significant increase in the world community’s interest in minerals that belong to the group of critical raw materials. The article presents generalized data on the ore-bearing zircon-rutile-ilmenite deposits of the Livoberezhniy placer district of the Ukrainian placer province. This area has unique paragenetic characteristics, as it is located in the junction zone of three geostructural units: the Dnipro-Donetsk depression, the northeastern slope of the Ukrainian crystalline shield, and the Kalmius-Toretsk depression of Donbas. The Livoberezhniy placer district includes the Vovchansk, Voskresenivsk, Southern, Nova-Mykolaivka, North-Samarsk, Yuriivsk and Petropavlivsk zircon-rutile-ilmenite deposits. These deposits are located in the sediments of the Bereka and Novi Petrivtsi suites. The Petropavlivsk and Yuriivsk deposits have a two-layer structure, the rest is belongs to the deposits of the only Novi Petrivtsi suite. The genesis of deposits is buried coastal-marine placers. All deposits have a slight dip of the ore sand layers in a north-east direction, which outlines the general slope of the water basin floor. Today, the Vovchansk zircon-ilmenite-rutile deposit is being developed by DEMURINSKY GZK LLC. On the basis of the results of geological prospecting and geological exploration conducted in the 60s and 70s of the last century, maps of the strength of the ore stratum and the distribution of ore components (ilmenite, rutile, zircon) were constructed. The visualization data was built for the Voskresenivsk, Southern, Nova-Mykolaivka, North-Samarsk, Yuriivsk and Petropavlivsk deposits. An analysis of the obtained data was carried out and a number of conclusions were drawn regarding the distribution of ore components for each of the deposits.
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Badli, Nur Afiqah, Rusmidah Ali, and Leny Yuliati. "Influence of Zirconium Doped Titanium Oxide towards Photocatalytic Activity of Paraquat." Advanced Materials Research 1107 (June 2015): 377–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.377.
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The heterogeneous photocatalyst based on titanium dioxide has been widely investigated as an attractive treatment method for water pollution. Herbicide like paraquat dichloride is one of the toxic organic pollutants which is harmful to human and animal and is still being used in agricultural sectors. TiO2doped with zirconium element has been proven to enhance the photocatalytic activity of TiO2from the previous study. Therefore in this study, photodegradation of paraquat dichloride (1,1-dimethyl-4,4’-bipyridylium dichloride) under UV irradiation was studied using TiO2and Zr doped TiO2prepared via modified sol gel method as photocatalysts. The photocatalytic activity was increased in the presence of zirconium as dopant compared to TiO2. Various calcination temperatures range from 450°C to 1000°C and dopant ratio (10:90, 20:80 and 30:70) were applied to optimize the working condition. Significant enhancement was obtained using Zr doped TiO2(20:80) calcined at 750°C which gave 79.63% degradation of paraquat compared to TiO2calcined at 450°C and 750°C which were 22.31% and 11.57%. X-ray diffraction (XRD) diffratogram of Zr doped TiO2photocatalyst showed a mixture of anatase/rutile TiO2crystalline structures at 750°C. Nanosized photocatalyst with spherical morphology was observed by Field Emission Scanning Electron Microscopy (FESEM). The surface area measured by nitrogen adsorption analysis showed an increment from 8.43m2/g to 46.35m2/g compared to undoped catalyst calcined at 450°C.
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NAKAZAWA, Chihiro, Hafiz Ur REHMAN, Hiroshi YAMAMOTO, and Tehseen ZAFAR. "Zirconium in rutile thermometry from garnet granulites of the Jijal complex of Kohistan arc, NW Himalaya." Journal of Mineralogical and Petrological Sciences 115, no. 2 (2020): 152–61. http://dx.doi.org/10.2465/jmps.191226.
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Bukała, Michał, Jarosław Majka, Katarzyna Walczak, Adam Włodek, Melanie Schmitt, and Anna Zagórska. "U-Pb Zircon Dating of Migmatitic Paragneisses and Garnet Amphibolite from the High Pressure Seve Nappe Complex in Kittelfjäll, Swedish Caledonides." Minerals 10, no. 4 (March 25, 2020): 295. http://dx.doi.org/10.3390/min10040295.
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The Seve Nappe Complex exposed in the Kittelfjäll area of the northern Scandinavian Caledonides comprises a volcano-sedimentary succession representing the Baltica passive margin, which was metamorphosed during the Iapetus Ocean closure. Garnet amphibolites, together with their host migmatitic paragneisses, record a potential (U)HP event followed by decompression-driven migmatization. The garnet amphibolites were originally thought to represent retrogressively altered granulites. The petrological and geochemical features of a studied garnet amphibolite allow for speculation about a peridotitic origin. Zirconium (Zr) content in rutile inclusions hosted in garnet in paragneisses points to near-peak temperatures between 738 °C and 780 °C, which is in agreement with the c. 774 °C obtained from the matrix rutile in the garnet amphibolite. The matrix rutile in multiple paragneiss samples records temperatures below 655 °C and 726 °C. Whereas the LA-ICP-MS U-Pb dating of zircon cores revealed the age spectrum from Paleoproterozoic to early Paleozoic, suggesting a detrital origin of zircon cores in paragneisses, the metamorphic zircon rims show an Early Ordovician cluster c. 475–469 Ma. Additionally, zircon cores and rims from the garnet amphibolite yielded an age of c. 473 Ma. The REE patterns of the Caledonian zircon rims from the paragneisses show overall low LREE concentrations, different from declining to rising trends in HREE (LuN/GdN = 0.49–38.76). Despite the textural differences, the cores and rims in zircon from the garnet amphibolite show similar REE patterns of low LREE and flat to rising HREE (LuN/GdN = 3.96–65.13). All zircon rims in both lithologies display a negative Eu anomaly. Hence, we interpret the reported ages as the growth of metamorphic zircon during migmatization, under granulite facies conditions related to exhumation from (U)HP conditions.
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Albiter, Luis A., Kathleen O. Bailey, Jose Fernando Godinez Salomon, and Christopher P. Rhodes. "Ruthenium-Zirconium Oxides As Highly Stable Oxygen Evolution Electrocatalysts." ECS Meeting Abstracts MA2022-02, no. 44 (October 9, 2022): 1648. http://dx.doi.org/10.1149/ma2022-02441648mtgabs.
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The further development and utilization of proton exchange membrane water electrolyzers (PEMWEs) is hindered by the cost, activity, and stability of the oxygen evolution reaction (OER) electrocatalyst. Iridium oxide (IrOx) is currently the go-to OER electrocatalyst, as it has been shown to have relative high activity and stability when compared to other OER active catalysts. However, iridium is one of the rarest elements in the Earth’s crust and therefore cost is a major limitation of iridium-based electrocatalysts. Ruthenium oxide (RuO2) is a highly active OER catalyst; although, it is highly unstable in acidic media and undergoes catalyst degradation over time. We investigated modifying RuO2 by substituting zirconium, which is highly stable in acidic conditions, to provide an electrocatalyst with increased stability. Our study explored the effect of low and moderate zirconium concentrations within RuO2 (Ru1-xZrxO2) on the structure, morphology, OER activity, and stability. The structure and morphology were characterized by X-ray diffraction and scanning electron microscopy. Preliminary results from XRD showed no observable phase separation at low Zr concentrations, and peak shifts were indicative of the incorporation of the larger Zr ion into the crystal structure of rutile RuO2. The OER activities and stabilities of Ru1-xZrxO2 were measured using a rotating disk electrode configuration and compared with RuO2. Our preliminary results show that the OER activity and stability are strongly affected by the addition of Zr and there may be an optimal concentration range for obtaining a balance between OER activity and stability. Our work furthers the understanding of how to develop OER electrocatalysts with increased stability while maintaining a high OER activity, which is crucial to the large-scale adoption of PEMWE’s.
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Rehman, Hafiz Ur, Yoshiyuki Iizuka, Hao-Yang Lee, Sun-Lin Chung, Zhanzhan Duan, Chunjing Wei, Tahseenullah Khan, Tehseen Zafar, and Hiroshi Yamamoto. "Zirconium in rutile thermometry of the Himalayan ultrahigh-pressure eclogites and their retrogressed counterparts, Kaghan Valley, Pakistan." Lithos 344-345 (November 2019): 86–99. http://dx.doi.org/10.1016/j.lithos.2019.06.017.
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Korol, Dmytro, Artem Yefimenko, and Mykhailo Korol. "COMPARISON OF THE CONDITION OF THE PERI-IMPLANT ORAL MUCOUS ACCORDING TO THE RESULTS OF DIGITAL MICROSCOPY." ScienceRise, no. 6 (December 30, 2020): 68–73. http://dx.doi.org/10.21303/2313-8416.2020.001558.
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The object of the study there is a level of hyperemia of the mucous membrane around the installed intraosseous dental implants with different coating material according to the results of histogram analysis of digital microscopy. The problem to be solved – evaluation of the degree of hyperemia of the periimplant mucosa around intraosseous dental implants coated with rutile, in comparison with titanium implants of VT-6 alloy after prosthetics. Main scientific results: Analysis of digital images using histogram evaluation of the red component of the spectrum showed that 1 month after prosthetics in group 1, which included 20 patients who had intraosseous implants made of titanium alloy TiV6Al (VT-6), the above indicator increased to 191 (St.Err. 4.45). The difference was 4 conventional units. Similarly, in group 2 (16 people) who had intraosseous zirconium implants, there was an increase in the quantitative rate after prosthetics by 9 conventional units, and its value was 194 conventional units (St.Err. 3.64). Since increasing numerical values and shifting the digital histogram to the right is an objective criterion for reducing the intensity of redness, it can be concluded that there is a reduction of mucosal irritation after orthopedic treatment with a predominance of this process in the group of patients who received intraosseous dental implants coated with rutile. The area of practical use of research results: Since the authors first studied the reaction of the peri-implant mucosa in contact with various implant materials at the stages of orthopedic treatment, this is the basis for the introduction into general medical practice of intraosseous dental implants made in Ukraine using rutile application technology. The area of application of an innovative technological product - it is a dental implant practice. The obtained results will allow to use more widely Ukrainian implants of non-demountable construction with a high level of surface preparation, for the purpose of further orthopedic treatment with the use of non-removable metal-ceramic dentures.
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Dmitriev, A. N., A. A. Smorokov, A. S. Kantaev, D. S. Nikitin, and G. Yu Vit’kina. "Fluorammonium method of titanium slag processing." Izvestiya. Ferrous Metallurgy 64, no. 3 (April 9, 2021): 178–83. http://dx.doi.org/10.17073/0368-0797-2021-3-178-183.
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Titanium dioxide is the most common titanium-containing product on the world market, and the demand for it is increasing. The global consumption of TiO2 is 7 – 7.5 million tons annually. Titanium dioxide is mainly obtained from ilmenite and rutile concentrates. The largest producers are China, USA, Germany, UK, Mexico, and Saudi Arabia. In addition to the natural resources of titan, there are man-made sources. This type of resource includes titanium-containing slags obtained as a result of pyrometallurgical processing of ores and concentrates containing titanium dioxide. These slags, in addition to titanium dioxide, contain silicon in the form of dioxide, silicates or aluminosilicates, whose chemical processing is difficult due to their high melting point (more than 2000 °C) and the chemical stability of these compounds in mineral acids (sulfuric, nitric, hydrochloric). Processing of such raw materials is carried out by “classical” chlorine and sulfuric acid methods. The use of fluorides in industry is realized in the production of aluminum, zirconium, uranium, beryllium, niobium, etc., which indicates the possibility of using fluoride methods for titanium slags processing. The article discusses a method for producing titanium dioxide based on the use of ammonium hydrodifluoride NH4HF2 , which has a high reactivity to a number of chemically resistant oxides (oxides of silicon, titanium, aluminum, etc.). The fluoroammonium method for processing titanium slag using NH4HF2 involves slag decomposition of in NH4HF2 melt followed by silicon admixture sublimation. Cleaning from iron, aluminum and other impurities is carried out using a solution of NH4HF2. Further precipitation of titanium with treatment of the precipitate by AlCl3 and ZnCl2 solutions followed by calcination allows to obtain a rutile modification of titanium dioxide.
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Manriquez, M. E., M. Picquart, X. Bokhimi, T. López, P. Quintana, and J. M. Coronado. "X-Ray Diffraction, and Raman Scattering Study of Nanostructured ZrO2-TiO2 Oxides Prepared by Sol–Gel." Journal of Nanoscience and Nanotechnology 8, no. 12 (December 1, 2008): 6623–29. http://dx.doi.org/10.1166/jnn.2008.18436.
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In the present work, we study the phase composition of ZrO2-TiO2 system by means of XRD and Raman spectroscopy, using also TG-ATD, and N2 adsorption isotherms as complementary characterization techniques. TiO2-ZrO2 samples of selected compositions (0, 10, 90, 50 and 100% in weight of TiO2) were prepared by sol–gel method and annealed at three different temperatures (400, 600 and 800 °C). Structural characterization reveals that only the pure oxides are crystalline at 400 °C: TiO2 as anatasa with a minor brookite component, and ZrO2 as a mixture of tetragonal (majority) and monoclinic phases. Following the 600 °C calcination, the TiO2-ZrO2 50–50% sample forms the ZrTiO4 mixed oxide, although this materials remains partly amorphous. In contrast, samples with higher and lower TiO2 content form solid solutions with, respectively, anatasa and tetragonal ZrO2 structures. Zirconium incorporation into the TiO2 lattice leads to the expansion of the unit cell parameters, and it stabilizes the anatase phase, hindering its transformation into rutile. Similarly, dissolving titanium atoms into the ZrO2 structure delays the transformation from the tetragonal to the monoclinic polymorph.
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Georgievskiy, A. F., and V. M. Bugina. "Phosphorites and Glauconites as Additional Reserves in the Development of Titanium-Zirconium Sands of the Centralnoye Deposit (Tambov Region of Russia)." IOP Conference Series: Earth and Environmental Science 988, no. 2 (February 1, 2022): 022031. http://dx.doi.org/10.1088/1755-1315/988/2/022031.
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Abstract After the Soviet Union demise, Russia was plagued by severe titanium resource problems. The bulk of titanium concentrates is imported from Ukraine. But Russia has its own titanium resources not lesser than in leading countries of the world (China, Brazil, South Africa). Ores form both primary and alluvial deposits, including those located in economically developed regions. The better example is the ancient marine placer of the Centralnoye deposit in the Rasskazovsky district of the Tambov region. In addition to ilmenite, rutile and zircon, ore sands also include phosphates and glauconite. The deposit was discovered in the middle of the last century and, after geological prospecting, was classified as one of the ten largest world objects of placer titanium ores. Despite this, for many years the Centralnoye deposit remained abandoned, since by that time, in the Soviet Union in Ukraine, several mining plants were already operating, which satisfied the industry’s demand for titanium. Today Russia is in dire need of titanium raw materials and the question of the need to develop the deposit has been repeatedly raised. This topic is being discussed especially actively today since a decision has been made on the expediency of its development. However, in the modern market environment, the implementation of this decision is an extremely difficult task. Here, the factors that can reduce operating costs that can improve the economic performance of mining and processing of ore sands become important. These factors include mining and use of both phosphorites and glauconites contained in titanium-zirconium ores and in the “overburden” rocks. The article describes the technogenic waste (tailings) of titanium - zirconium ores. Their material, mineral and granulometric composition is considered, and the technological properties of phosphorites and glauconites are described in the article. On the basis of experimental data, it has been shown that the accumulated concentrates represent high-quality raw materials for the production of phosphate rock and effective phosphorus and potassium ameliorants.
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Dubyna, О., S. Kryvdik, V. Belskyy, and О. Vyshnevskyi. "ACCESSOR MINERALS OF RARE METALS IN THE GRORUDITES OF EASTERN AZOV (UKRAINE)." Visnyk of Taras Shevchenko National University of Kyiv. Geology, no. 2 (89) (2020): 36–41. http://dx.doi.org/10.17721/1728-2713.89.05.
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Unlike other Precambrian platforms and shields, alkaline granites and their hypabyssal and effusive variaties in Ukraine have limited distribution. In Eastern Azov region dike analogs of alkaline granites (grorudites) are known. They are different in chemical and mineral composition and considered as analogs of pantellerites (aegirine hihg-Ti) and comendites (amphibole low-Ti). The high-Ti aegirine grorudites are more intensively enriched with incompatible rare elements (REE, Zr, Nb) compared with their low-Ti varieties. Despite the high or elevated concentration of HFSE in grorudites, there are few of their own minerals in these rocks. Thus, in high-Ti grorudites there have been identified such minerals of rare elements as monazite-(Ce), bastnäsite-(Ce), britholite-like mineral and rare earth apatite, zircon and undiagnosed zirconium mineral, whereas only zircon and niobium-containing rutile are diagnosed in amphibole one. These minerals are very small in size, the largest of them can reach 15-20 μm (sometimes up to 50 μm), although most of them do not exceed 10 μm (usually 5-6 μm). It is assumed that a significant part of rare metals are isomorphically included in rock-forming minerals (alkaline pyroxenes and amphiboles), and zirconium minerals, at least part of them, are secondary and formed as result of changing of primary sodium (eudialyte, catapleite, ilerite) or calcium (gittingsite) zirconosilicates which are more typical for peralkaline (agpaitic) rocks. Taking into account the peculiarities of the mineral composition, geochemical features and rare-earth mineralization of the Azov region, there is reason to believe that the HFSE mineralization of these rocks is a consequence of the differentiation of the primary igneous silica unsaturated melt(s). Secondary hydrothermal processes are weakly manifested in the studied rocks and probably presented by replacement of primary accessory minerals. Elevated or high concentrations of Nb in high-Ti grorudites and absence of Nb-minerals may indicate that the PTcondition of differentiation of these rocks (low F concentration, high fO2, and hypabyssal conditions of crystallization) did not contribute to their crystallization. The presence of grorudites in this region increase the prospects of discovering small alkaline granite massifs (holocrystalline analogues of grorudites) to which deposits and/or occurrences of Nb, REE, Zr, Sn, Be can be related
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Novikov, D. A., A. F. Sukhorukova, and T. V. Korneeva. "Hydrogeology and hydrogeochemistry of the Zaeltsovsko-Mochishchensky zone of radon waters in the southern West Siberia." Geodynamics & Tectonophysics 9, no. 4 (December 9, 2018): 1255–74. http://dx.doi.org/10.5800/gt-2018-9-4-0394.
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The study aims at solving the fundamental and applied problems of hydrogeology and hydrogeochemistry of the Zaeltsovsko-Mochishchensky zone of radon waters in the northwestern district of the city of Novosibirsk. Novosibirsk is one of the few Russian cities built on granites that emit radon (222Rn). In geological terms, the study area is confined to the NW near-contact zone of the large Novosibirsk granitoid massif. The available data on radon in this area has not been scientifically consolidated yet. We used the methods of S.L. Shvartsev, N.M. Kruglikov, V.V. Nelyubin, O.N. Yakovlev, and V.M. Matusevich and software packages Visual Minteq, PhreeqC, WATEQ4f and HG-32 and obtained physical and chemical calculations for the forms of migration of trace elements in radon waters and estimated the degrees of radon water saturation with rock-forming minerals. The data from hydrogeological profiles and hydrogeochemical sampling (118 samples from 57 water wells and sources) were analyzed. Radon waters are fissure-type, cold (6–10 °С) and occur at a depth of 50–200 m. By their chemical composition (according to the classification proposed by S.А. Shchukarev), the waters are mainly hydro-carbonate calcium and hydro-carbonate calcium-sodium; the total mineralization amounts to 322–895 mg/dm3. All the water wells drilled in granites and near-contact hornfels were tested for radon. It is revealed that the 222Rn concentration in water varies widely, from 11 to 801 Bq/dm3. Therefore, such waters are classified as low-radon and moderate-radon mineral waters (according to the classification proposed by N.I. Tolstikhin). In the wells drilled in hornfels, the 222Rn concentration in water is 37–241 Bq/dm3. The concentrations of 238U and 226Ra do not exceed 0.098 and 1.9∙10–9 mg/dm3, respectively. Physicochemical simulation shows that Ag+, Ba2+, Zn2+, Ni2+, Mn2+, Sr2+, Fe2+ migrate mainly as free ions, while Be2+, Fe3+, Zr4+, Ti4+ migrate as hydroxide complexes. Uranium is mainly present in uranyl-carbonate complexes of calcium: Ca2UO2(CO3)3(aq) (61–75 %) and CaUO2(CO3)32– (25–36 %). Calculations show abundant saturation of the waters with calcite, dolomite, ferrihydrite, greenalite, hausmannite, manganite, quartz, rutile, siderite, lepidocrocite, goethite, and pyrolusite. The mineral phases, such as aragonite, barite, chalcedony, cristobalite, vaterite, and amorphous silicon dioxide are in equilibrium. Several samples show saturation of the waters with relatively rare phosphorus-containing minerals: hydroxyapatite, manganese hydrogen phosphate, cerargyrite, and lead molybdate. The radon waters are not saturated with monohydrocalcite, calcium molybdate, celestite, chrysotile, copper hydroxide, copper molybdate, epsomite, huntite, amorphous and crystalline iron hydroxide (II), gypsum, iron molybdate (II), magnesite, lansfordite, Na-jarosite, nesquehonite, powellite, strontianite, tenorite, witherite, and zirconium dioxide.
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Coste, Sandrine, Ghislaine Bertrand, Christian Coddet, Eric Gaffet, Horst Hahn, H. Sieger, Cathy Meunier, and Serge Vives. "Microstructural and Mechanical Characterization of Mechanically-Activated Plasma-Sprayed Nanostructured Al2O3-TiO2 and Al2O3-ZrO2 Coatings." Advances in Science and Technology 45 (October 2006): 1224–29. http://dx.doi.org/10.4028/www.scientific.net/ast.45.1224.
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Granulated nanostructured alumina/titania and alumina/zirconia powders were used to achieve coatings by atmospheric plasma spraying. Raw materials and mechanically activated ceramic mixtures (alumina with 13wt% and 44wt% of titania or 40wt% and 80wt% of zirconia) have been considered to produce the sprayable powders. Effects of various plasma spray conditions (primary Ar and secondary H2 gas flow rates, arc intensity) on the microstructure, phase content and microhardness of the coatings have been evaluated. It has been shown by SEM observations that the coatings exhibit a lamellar structure consisting in fully melted and partially melted areas including porosity, ranging from 10 to 30vol.%. The phase changes (from αAl2O3 to γAl2O3, from anatase to rutile for TiO2, Al2TiO5) or structural changes that occur during the plasma spraying of the nanostructured powders were investigated by XRD and related to the processing conditions and in turn to the amount of unmelted powder.
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Daigle, Jean-Christophe, and Jerome P. Claverie. "A Simple Method for Forming Hybrid Core-Shell Nanoparticles Suspended in Water." Journal of Nanomaterials 2008 (2008): 1–8. http://dx.doi.org/10.1155/2008/609184.
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Core-shell hybrid nanoparticles, where the core is an inorganic nanoparticle and the shell an organic polymer, are prepared by a two-step method. Inorganic nanoparticles are first dispersed in water using poly(acrylic acid) (PAA) prepared by reversible addition fragmentation chain transfer (RAFT) polymerization as dispersant. Then, the resulting dispersion is engaged in a radical emulsion polymerization process whereby a hydrophobic organic monomer (styrene and butyl acrylate) is polymerized to form the shell of the hybrid nanoparticle. This method is extremely versatile, allowing the preparation of a variety of nanocomposites with metal oxides (alumina, rutile, anatase, barium titanate, zirconia, copper oxide), metals (Mo, Zn), and even inorganic nitrides (Si3N4).
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Coste, Sandrine, Ghislaine Bertrand, Christian Coddet, Eric Gaffet, Horst Hahn, H. Sieger, M. A. Rodriguez, Cathy Meunier, and Serge Vives. "Microstructural Transformations of Al2O3-TiO2 and Al2O3-ZrO2 Powders Induced by High-Energy Ball-Milling." Advances in Science and Technology 45 (October 2006): 303–8. http://dx.doi.org/10.4028/www.scientific.net/ast.45.303.
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Superior properties of nanostructured Al2O3 based materials, such as higher hardness and fracture toughness, have been evidenced. In order to optimize their manufacturing, the mechanical activation of the starting powders (Al2O3-TiO2 and Al2O3-ZrO2) was studied. In the present work, Al2O3 powders blended with 13wt% and 44wt% of titania or 20wt% and 80wt% of yttria partially stabilized zirconia have been high-energy ball-milled using a planetary mill, P4 (Fritsch) with steel vials and balls. The effect of the milling time and operating parameters, such as shock energy and friction to total energy ratio, on the powder structural and microstructural evolutions has been determined by SEM, XRD and BET. The transformation of the metastable anatase TiO2 phase into the high pressure TiO2 II phase and rutile phase was evidenced, simultaneously to the decrease of the alumina crystallite size, in the Al2O3-TiO2 system. In the Al2O3-ZrO2 system, the transformation of the monoclinic phase and the decrease of the alumina and tetragonal zirconia crystallite size have been observed.
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Silvestri, Siara. "PHOTOCATALYTIC EFFICIENCY OF TiO2 IN BIOTEMPLATES FORM IN THE DECOLORATION OF ORGANIC DYE AND INHIBITION OF E. COLI GROWTH." JOURNAL OF ADVANCES IN CHEMISTRY 12, no. 3 (February 16, 2016): 4247–55. http://dx.doi.org/10.24297/jac.v12i3.2165.
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Anatase TiO2 is widely used for pollutant degradation due to its photocatalytic property. Exposure of the surface to UV radiation (sunlight or artificial) generates an electron-hole pair that is responsible for the formation of free radicals such as O2•−in the presence of atmospheric oxygen and HO• in the presence of water. Biomorphic TiO2 plates were produced by infiltration of paper with titanium isopropoxide (TTiP) solution followed by hydrolysis in NH4OH and calcination at temperatures up to 600-1000 ºC, as a new way of fixing TiO2 with the aim of delaying the phase transition from anatase (photoactive) to rutile (inactive). In order to study the effect of addition of zirconia as a dopant on the microstructure and the phase transition from anatase to rutile, the same procedure was used, but with the addition of 5% (m/m) of ZrO(NO3)2 to TTiP. The biomorphic materials were characterized by XRD, specific surface area measurement (using the BET method), EPR, and SEM. Their photocatalytic efficiencies were evaluated in the decoloration of Orange II dye and the inhibition of growth of E. coli bioluminescent bacteria. Using 5% Zr-doped TTiP, with calcination at 800 ºC, bacterial growth was reduced by 23% after 180 minutes, and 70% dye decoloration was achieved in30 hours.
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Zhang, Yunsheng, Hengbo Yin, Aili Wang, Chun Liu, Longbao Yu, Tingshun Jiang, and Ying Hang. "Evolution of zirconia coating layer on rutile TiO2 surface and the pigmentary property." Journal of Physics and Chemistry of Solids 71, no. 10 (October 2010): 1458–66. http://dx.doi.org/10.1016/j.jpcs.2010.07.013.
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Lin, Ming-Hong, and Moo-Chin Wang. "Phase transformation and characterization of TiO2 and ZrO2 addition in the Li2O–Al2O3-SiO2 gels." Journal of Materials Research 11, no. 10 (October 1996): 2611–15. http://dx.doi.org/10.1557/jmr.1996.0328.
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Glass-ceramic powders with a composition of Li2O · Al2O3 · 4SiO2 (LAS) have been synthesized by the sol-gel technique using LiOCH3, Al(OC2H5)3, Si(OC2H5)4, Ti(OC2H5)4, and Zr(OC2H5)4 as starting materials and the phase transformation behavior during calcination has been investigated. Differential thermal analysis (DTA), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were utilized to determine the thermal behavior of the gels. Considering the LAS gels with 6.0 wt. % TiO2 and various wt. % ZrO2 content, and peak position of the β-spodumene phase formation in DTA curves was shifted to a higher temperature when the ZrO2 content was increased. The activation energy of β-spodumene crystallization was 283.8 kcal/mol for LAS gels with 6.0 wt. % TiO2 and 2.0 wt. % ZrO2. Unlike foregoing studies for LAS gels, during calcination of the dried LASTZ gels from 800 °C to 1200 °C neither β-eucryptite nor γ-spodumene was noted to be present. The crystallized phases comprised of β-spodumenes as the major phase and rutile (TiO2) together with zirconia (ZrO2) are precipitated as minor phases.
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Leite, José Yvan Pereira, Franciolli Araújo, and Bruna Marcela S. Araújo. "CARACTERIZAÇÃO MINERALÓGICA PARA FINS TURÍSTICOS DAS AREIAS DE PONTA NEGRA – NATAL/RN/BRASIL." HOLOS 3 (July 3, 2014): 61. http://dx.doi.org/10.15628/holos.2014.1834.
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A praia de Ponta Negra esta localizada em Natal, capital do Rio Grande do Norte, sendo esta o principal cartão postal do Estado que é caracterizado por uma grande duna margeada pela Mata Atlântica. Com o objetivo de gerar produtos voltados para desenvolvimento do turismo, associando temas da área mineral foi coletada amostra próximo ao Morro do Careca, seguida de classificação granulométrica, separação em meio denso e identificação mineralógica com técnicas de microscopia ótica e em MEV. Em seguida, as imagens foram tratadas e gerados produtos associando os minerais identificados (quarzto, epidoto, rutilo, magnetita, titanita, ilmenita, zirconita) na areia de praia com a paisagem da região. As imagens deverão ser utilizadas na geração de produtos, tais como cartões postais, pôsteres, camisetas, bateias, folders, livros, entre outros. Este trabalho elevará a divulgação e valoração da área mineral, bem como fomentará empreendimentos voltados para a divulgação científica.
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Haba, Makiko K., Yi-Jen Lai, Jörn-Frederik Wotzlaw, Akira Yamaguchi, Maria Lugaro, and Maria Schönbächler. "Precise initial abundance of Niobium-92 in the Solar System and implications for p-process nucleosynthesis." Proceedings of the National Academy of Sciences 118, no. 8 (February 19, 2021): e2017750118. http://dx.doi.org/10.1073/pnas.2017750118.
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The niobium-92–zirconium-92 (92Nb–92Zr) decay system with a half-life of 37 Ma has great potential to date the evolution of planetary materials in the early Solar System. Moreover, the initial abundance of the p-process isotope 92Nb in the Solar System is important for quantifying the contribution of p-process nucleosynthesis in astrophysical models. Current estimates of the initial 92Nb/93Nb ratios have large uncertainties compromising the use of the 92Nb–92Zr cosmochronometer and leaving nucleosynthetic models poorly constrained. Here, the initial 92Nb abundance is determined to high precision by combining the 92Nb–92Zr systematics of cogenetic rutiles and zircons from mesosiderites with U–Pb dating of the same zircons. The mineral pair indicates that the 92Nb/93Nb ratio of the Solar System started with (1.66 ± 0.10) × 10−5, and their 92Zr/90Zr ratios can be explained by a three-stage Nb–Zr evolution on the mesosiderite parent body. Because of the improvement by a factor of 6 of the precision of the initial Solar System 92Nb/93Nb, we can show that the presence of 92Nb in the early Solar System provides further evidence that both type Ia supernovae and core-collapse supernovae contributed to the light p-process nuclei.
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Yang, Yuanjun, Yingxue Yao, Benjian Zhang, Hui Lin, Zhenlin Luo, Chen Gao, Cong Zhang, and Chaoyang Kang. "Investigating Metal–Insulator Transition and Structural Phase Transformation in the (010)-VO2/(001)-YSZ Epitaxial Thin Films." Materials 11, no. 9 (September 13, 2018): 1713. http://dx.doi.org/10.3390/ma11091713.
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The VO2 thin films with sharp metal–insulator transition (MIT) were epitaxially grown on (001)-oriented Yttria-stabilized zirconia substrates (YSZ) using radio-frequency (RF) magnetron sputtering techniques. The MIT and structural phase transition (SPT) were comprehensively investigated under in situ temperature conditions. The amplitude of MIT is in the order of magnitude of 104, and critical temperature is 342 K during the heating cycle. It is interesting that both electron concentration and mobility are changed by two orders of magnitude across the MIT. This research is distinctively different from previous studies, which found that the electron concentration solely contributes to the amplitude of the MIT, although the electron mobility does not. Analysis of the SPT showed that the (010)-VO2/(001)-YSZ epitaxial thin film presents a special multi-domain structure, which is probably due to the symmetry matching and lattice mismatch between the VO2 and YSZ substrate. The VO2 film experiences the SPT from the M1 phase at low temperature to a rutile phase at a high temperature. Moreover, the SPT occurs at the same critical temperature as that of the MIT. This work may shed light on a new MIT behavior and may potentially pave the way for preparing high-quality VO2 thin films on cost-effective YSZ substrates for photoelectronic applications.
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Trujillo, Alejandro, Mirian Mejía, Jorge Bravo, María Ceron, and Eleazar Rufasto. "ESTUDIO MINERALÓGICO DE UN SUELO PERTENECIENTE AL FUNDO VIVERO FRUTÍCOLA MOTUPE LAMBAYEQUE, USANDO TÉCNICAS ANALÍTICAS Y COMPLEMENTARIAS." Revista Cientifica TECNIA 19, no. 2 (May 10, 2017): 29. http://dx.doi.org/10.21754/tecnia.v19i2.115.
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Los materiales liberados durante el proceso de intemperización del suelo pueden ser removidos del sistema en el proceso de drenaje del agua o pueden reaccionar en el sistema para formar una variedad de productos cristalinos o amorfos. Los productos de reacción que se observan comúnmente, son los minerales de arcilla y los óxidos e hidróxidos de aluminio y hierro. La caracterización de estos materiales es de vital importancia porque son ellos quienes reflejan de mejor manera los efectos a largo plazo del entorno químico y de los mecanismos de drenaje del suelo. Además, estos materiales tienen marcada influencia en muchas propiedades del suelo. En el presente trabajo se reportan los resultados de la caracterización mineralógica y elemental de una muestra de suelo proveniente del Fundo Vivero Frutícola Motupe, perteneciente a la Facultad de Agronomía de la Universidad Nacional Pedro Ruiz Gallo de Lambayeque, para lo cual se hace uso de las técnicas de Fluorescencia de rayos X (FRX), difractometría de rayos X (DRX) y espectroscopia Mössbauer por transmisión (EMT). Se incluye además los procedimientos de análisis de rutina como pH, conductividad eléctrica, porcentaje de carbonatos y bicarbonatos. Se analizó la muestra en bruto Mo06. DRX permitió la identificación de Cuarzo, Illita, Ortoclasa y Albita en la muestra en bruto. EMT permitió identificar, en la muestra en bruto, un sexteto adjudicado a la Hematita, un doblete central que podría ser adjudicado a un óxido de hierro en estado superparamagnético y dos dobletes adjudicados a la Illita. La composición química fue determinada haciendo uso de FRX. Se detectaron Hierro y Silicio como elementos mayoritarios y Azufre, Cloro, Potasio, Calcio, Titanio, Vanadio, Cromo, Manganeso, Níquel, Cobre, Zinc, Rubidio, Estroncio y Zirconio como elementos minoritarios. Palabras clave.-Difractometría de rayos X, Espectroscopia Mössbauer, Fluorescencia de rayos X, Súper paramagnetismo. ABSTRACTThe products derived from the weathering process of soils can be removed from this system by the process of water drainage or they can react in this system by forming a variety of crystall or amorphous products. The reaction products that are most commonly observed are the clay minerals, the oxides and hydroxides iron and aluminum. The characterization of these materials is of vital importance because they reflect at its best the long term effects of the chemical environment and draining mechanisms of soils. Moreover, they have a marked influence on many soil properties. This paper reports the results of the elemental and mineralogical characterization of a soil sample from the Motupe orchard and nursery farm that belongs to the Pedro Ruiz Gallo National University, Lambayeque, using X-ray Fluorescence (XRF), X-ray Diffraction (XRD) and Transmission Mössbauer Spectroscopy (EMT) techniques were used. Other routine soil analysis were also applied such as texture, pH, electrical conductivity and percent content of carbonates and bicarbonates. The Mo06 sample bulk was tested. By XRD was identified. Quartz, Illite, Orthoclase and Albite. In the bulk sample by TMS was identified a sextet attributed to Hematite, a central doublet that could be assigned to an iron oxide in the super paramagnetic state and two doublets assigned to the Illite. The chemical composition, for elements with atomic number higher than 13, was determines by XRF. Iron and silicon were determine to be the major components, and Sulfur, Chlorine, Potassium, Calcium, Titanium, Vanadium, Chrome, Manganese, Nickl, Copper, Zinc, Rubidium, Strontium and Zirconium as minor components. Number larger than 13, and Zinc, Rubidium, Strontium and Zirconium as minor components. Keywords.- X ray diffractometry, Mössbauer spectroscopy, X-ray fluorescence, Super paramagnetic.
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Wang, Wei Guang, Ming Xian Wang, Xian Jin Feng, and Jin Ma. "Effects of Deposition Rate on the Structural, Morphological and Optical Properties of Brookite TiO2 Films Prepared by MOCVD." Materials Science Forum 898 (June 2017): 1787–95. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1787.
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Compared to anatase and rutile TiO2, the brookite TiO2 (b-TiO2) is relatively seldom investigated, because it is difficult to be prepared. In order to explore a scientific and effective approach to prepare high quality b-TiO2 crystalline films, the effects of deposition rate on the properties of b-TiO2 films prepared on yttria-stabilized zirconia (YSZ) (110) substrates by metal organic chemical vapor deposition (MOCVD) were investigated in this study. The structural analyses indicated that the b-TiO2 film prepared with the lowest deposition rate of 1.25 Å/min had the best single crystalline quality for which the epitaxial relationship between the film and substrate was determined as b-TiO2(120) || YSZ(110) with an in-plane epitaxial relationship of b-TiO2[001]|| YSZ[001] and b-TiO2[20]||YSZ[10]. The RMS surface roughness of the obtained films decreased from 7.02 to 1.11 nm as the deposition rate decreased. The average transmittances of all the obtained b-TiO2 films exceeded 90% in the visible range. The optical band gaps increased from 3.54 to 3.63 eV as the deposition rate decreased. Apparently, the deposition rate has a significant influence on the structural, morphological and optical properties. Therefore, it provides a practicable way to manipulate such properties of b-TiO2 films for different applications in the field of transparent optoelectronic devices.
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Gleń, Marta A., and Barbara U. Grzmil. "Distribution of Additives in Single-Modified TiO2." MRS Proceedings 1373 (2012). http://dx.doi.org/10.1557/opl.2012.297.
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ABSTRACTIn the present work the influence of different modifiers, calculated to B2O3, CeO2, Sb2O3, ZnO, and ZrO2, on their distribution in TiO2 is investigated. The phase composition and phase transformation of prepared rutile-TiO2 is determined by the selective leaching method, ICP-AES, XRD and FT-IR techniques. The addition of Sb2O3 to TiO2 has no influence on the anatase–rutile phase transformation, CeO2 and ZrO2 act as inhibitors of the TiO2 phase transformation and the addition of ZnO or B2O3 to TiO2 accelerates rutile formation. It is observed that boron is located in TiO2 in the form of soluble B2O3, zinc partly reacts with titanium forming co-phase TiZn2O4 and antimony addition to TiO2 presumably causing the formation of a co-phase of Sb with Ti. Cerium forms a separate phase, CeO2, and reacts partly with titanium, probably creating co-phase, CexTi(1-x)O2 (for example Ce0.8Ti0.2O2). Zirconium addition in TiO2 forms separate ZrO2 phase and solid solution of Zr with Ti.
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"Prospects for the Practical Value of the Integrated Development of Poor Titanium-Zirconium Placers and Weathering Crusts in Kazakhstan." Недропользование 21, no. 1 (January 2021): 17–22. http://dx.doi.org/10.15593/2712-8008/2021.1.3.
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On the territory of the Republic of Kazakhstan there is a significant number of identified deposits related to weathering crusts and titanium-ilmenite placers, bearing industrial mineralization of rare and rare-earth elements. Deposits of placers and weathering crusts, formed as a result of bedrocks denudation in coastal and continental sedimentation conditions, form the basis of the mineral resource base of titanium-zirconium ores in the Republic of Kazakhstan. Titanium-zirconium deposits of placers and weathering crusts usually have low average contents of the main useful components (rutile, ilmenite, and zircon), while containing associated mineralization of valuable rare and rare earth elements. Various aspects of the complex development of poor titanium-zirconium placers, which are currently of no practical importance, are considered. Associated useful components of titanium-zirconium placers are usually represented by rare and rare earth elements, which are of practical importance in high-tech industries. The study of associated useful components in titanium-zirconium placers will allow considering the possibility of profitable exploitation and assessing the prospects for strengthening their mineral resource base. As a result of the review, analysis and assessment of known titanium-zirconium placers on the territory of Kazakhstan, the most promising ore occurrences have been identified, which may be of practical importance in their integrated development: Karaotkel deposit – increased contents of rare and rare earth elements in placer ores can be considered, not only as a source monomineral concentrates of ilmenite, zircon, quartz and quartzite, mica and feldspar ceramic raw materials, but also as a source of rare and rare earth elements; The Kundybai, Zayachye and Druzhba ore occurrences have the potential for the integrated development of titanium-zirconium placers with rare and rare-earth elements. The selected objects deserve prospecting and appraisal work with technical and economic studies of the possibility of integrated development.
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Stefanovsky, Sergey, Sergey Yudintsev, Boris Nikonov, and Olga Stefanovsky. "Rare Earth-Bearing Murataite Ceramics." MRS Proceedings 985 (2006). http://dx.doi.org/10.1557/proc-985-0985-nn04-10.
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AbstractPhase composition of the murataite-based ceramics containing 10 wt.% lanthanum, cerium, neodymium, europium, gadolinium, yttrium, zirconium oxides was studied. The ceramics were prepared by melting of oxide mixtures in glass-carbon ampoules in air at ∼1500° C. They are composed of predominant murataite-type phases and minor extra phases: rutile, crichtonite, perovskite, ilmenite/pyrophanite, and zirconolite (in the Zr-bearing sample only). Three murataite-related phases with five- (5C), eight- (8C), and three-fold (3C) elementary fluorite unit cell are normally present in all the ceramics. These phases form core, intermediate zone, and rim of the murataite grains, respectively. They are predominant host phases for the rare earth elements whose concentrations are reduced in a row: M-5C>M-8C>M-3C. Appreciate fraction of La and Ce may enter the perovskite phase.
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Bukała, Michał, Christopher J. Barnes, Pauline Jeanneret, Károly Hidas, Stanisław Mazur, Bjarne S. G. Almqvist, Karolina Kośmińska, Iwona Klonowska, Juraj Šurka, and Jarosław Majka. "Brittle Deformation During Eclogitization of Early Paleozoic Blueschist." Frontiers in Earth Science 8 (December 17, 2020). http://dx.doi.org/10.3389/feart.2020.594453.
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The Tsäkkok Lens of the Scandinavian Caledonides represents the outermost Baltican margin that was subducted in late Cambrian/Early Ordovician time during closure of the Iapetus Ocean. The lens predominantly consists of metasedimentary rocks hosting eclogite bodies that preserve brittle deformation on the μm-to-m scale. Here, we present a multidisciplinary approach that reveals fracturing related to dehydration and eclogitization of blueschists. Evidence for dehydration is provided by relic glaucophane and polyphase inclusions in garnet consisting of clinozoisite + quartz ± kyanite ± paragonite that are interpreted as lawsonite pseudomorphs. X-Ray chemical mapping of garnet shows a network of microchannels that propagate outward from polyphase inclusions. These microchannels are healed by garnet with elevated Mg relative to the surrounding garnet. Electron backscatter diffraction mapping revealed that Mg-rich microchannels are also delimited by low angle (<3°) boundaries. X-ray computed microtomography demonstrates that some garnet is transected by up to 300 μm wide microfractures that are sealed by omphacite ± quartz ± phengite. Locally, mesofractures sealed either by garnet- or omphacite-dominated veins transect through the eclogites. The interstices within the garnet veins are filled with omphacite + quartz + rutile + glaucophane ± phengite. In contrast, omphacite veins are predominantly composed of omphacite with minor apatite + quartz. Omphacite grains are elongated along [001] crystal axis and are preferably oriented orthogonal to the vein walls, indicating crystallization during fracture dilation. Conventional geothermobarometry using omphacite, phengite and garnet adjacent to fractures, provides pressure-temperature conditions of 2.47 ± 0.32 GPa and 620 ± 60°C for eclogites. The same method applied to a mesoscale garnet vein yields 2.42 ± 0.32 GPa at 635 ± 60°C. Zirconium-in-rutile thermometry applied to the same garnet vein provides a temperature of ∼620°C. Altogether, the microchannels, microfractures and mesofractures represent migration pathways for fluids that were produced during glaucophane and lawsonite breakdown. The microfractures are likely precursors of the mesoscale fractures. These dehydration reactions indicate that high pore-fluid pressure was a crucial factor for fracturing. Brittle failure of the eclogites thus represents a mechanism for fluid-escape in high-pressure conditions. These features may be directly associated with seismic events in a cold subduction regime.
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Xu, Huifang, and Yifeng Wang. "Microstructure Evolution and Weathering Reactions of Synroc Samples Crystallized from CaZrTi2O7 melts: TEM/AEM investigation and geochemical modeling." MRS Proceedings 556 (1999). http://dx.doi.org/10.1557/proc-556-47.
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AbstractScanning electron microscopy (SEM), transmission electron microscopy (TEM), and analytical electron microscopy (AEM) studies have been conducted on samples crystallized from a melt with a composition of zirconolite {(Ca0.9Gd0.1)Zr(Ti1.9Al0.1)2, O7}. The formationof a whole suite of Synroc minerals (zirconia, ZrTiO4, zirconolite, perovskite, and rutile) has been observed. The formation of these minerals follows the crystallization sequence of Ti-bearing zirconia → ZrTiO4 phase → Zr-rich zirconolite → Zr-poor zirconolite → rutile/perovskite. This sequence is induced by a fractional crystallization process, in which Zr-rich mineral phases tend to crystallize first, resulting in continuous depletion of Zr in melt. Consistent with this melt compositional evolution, Zr content in the zirconolite decreases from the area next to ZrTiO4 phase to the area next to rutile or perovskite. High-resolution TEM images show that there are no glassy phases at the grain boundary between zirconolite and perovskite. The fractional crystallization-induced textural heterogeneity may have a significant impact on the incorporation of radionuclides into crystalline phases and the resistance of radioniclides to leaching processes. Exsolution lamellae and multiple twinning result from the phase transition from tetragonal zirconia to monoclinic zirconia may decrease durability of the Synroc. Fast cooling of melt may produce more zirconolite phase and relatively uniform texture. In general, however, a Synroc prepared by a through-melt method is less uniform in texture than that prepared by a through-sol-gel method. The reaction path calculation for the alteration of U-bearing zirconolite in an oxidizing fluid shows that zirconolite is first altered into a perovskite-like phase (CaZrO3), followed by rutile (TiO2 ), and U6+ -bearing phases of soddyite [(UO2)2SiO42H20] and haiweeite [Ca(U02)2Si6O15·5H2O].
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Knyazev, O. A., S. V. Stefanovsky, S. V. Ioudintsev, B. S. Nikonov, B. I. Omelianenko, A. V. Mokhov, and A. I. Yakushev. "Phase Equilibria and Elements Partitioning in Zirconolite-Rich Region of Ca-Zr-Ti-Al-Gd-Si-O System." MRS Proceedings 465 (1996). http://dx.doi.org/10.1557/proc-465-401.
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ABSTRACTZirconolite-rich ceramics were produced by the cold crucible melting technique in an air atmosphere, at 1550±50 °C and 1 atm. Four samples with overall composition (in wt.%): 4.9–14.3 CaO; 19.0–41.3 ZrO2; 24.1–42.6 TiO2; 1.3–11.3 Al2O3; 6.8–30.0 Gd2O3, and 1.1–8.5 SiO2 have been studied. Total phases in the ceramics consist of major zirconolite and minor rutile, perovskite, zirconia, aluminium titanate, and glass. The Gd2O3 content in zirconolite reaches up to 31.4 wt.% corresponding to the formula: (Cao4,Gd0.7)Zri.0(Tii4,Alo 5)070. The data on the phase composition agree well with coupled Gd incorporation into the mineral structure. Ca(H) + Ti(IV) = Gd(III) + Al(III), and 2Gd(III) - Ca(II) + Zr(IV). The highest Gd contents observed in the other phases are 25.4 % for zirconia, 12.6 % in glass, 8.8 % in perovskite, and 1.4 % for rutile. The rest of the elements' distribution in the samples are analyzed.
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Kickelbick, Guido, and Ulrich Schubert. "Carboxylate-Substituted Oxotitanium and Oxozirconium Clusters as Structural Models for Titania- and Zirconia-Based Inorganic-Organic Hybrid Materials." MRS Proceedings 519 (1998). http://dx.doi.org/10.1557/proc-519-401.
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AbstractReaction of Ti(OR)4 or Zr(OR)4 with carboxylic acids resulted in the formation of crystalline carboxylate-substituted oxotitanium and oxozirconium clusters with different Ti/Zr : carboxylate ratios. Structural investigations showed that the cluster cores are rutile- or zirconia-like if the carboxylate : metal ratio does not exceed 1.33 (for Ti) or 2 (for Zr), respectively. When the carboxylate : metal ratio is increased beyond these values, more open clusters and eventually polymeric structures are obtained.
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White, T. J., R. C. Ewing, L. M. Wang, J. S. Forrester, and C. Montross. "Temperature Dependence of Amorphization for Zirconolite and Perovskite Irradiated with 1 Mev Krypton Ions." MRS Proceedings 353 (1994). http://dx.doi.org/10.1557/proc-353-1413.
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AbstractA transmission electron microscope investigation was made of zirconolites and perovskites irradiated to amorphization with 1 MeV krypton ions using the HVEM-Tandem Facility at Argonne National Laboratory. Three specimens were examined - a prototype zirconolite CaZrTi2O7, a gadolinium doped zirconolite Ca0.75Gd0.50Zr0.75Ti2O7and a uranium doped zirconolite Ca0.75U0.50Zr0.75Ti2O7. The critical amorphization dose Dc was determined at several temperatures between 20K to 675K. Dc was inversely proportional with temperature. For example, pure zirconolite requiring 10x the dose for amorphization at 475K compared with gadolinium zirconolite. Using an Arrhenius plot, the activation energy Ea for annealing in these compounds was found to be 0.129 eV and 0.067 eV respectively. The greater ease of amorphization for the gadolinium sample is probably a reflection of this element’s large cross section for interaction with heavy ions. Uranium zirconolite was very susceptible to damage and amorphised under 4 keV argon ions during the preparation of microscope specimens. In each sample, zirconolite coexisted with minor perovskite, reduced rutile (Magneli phases) and zirconia. These phases were more resistant to ion irradiation than zirconolite. Even for high gadolinium loadings, perovskite (Ca0.8Gd0.2TiO3) was 3-4 times more stable to ion irradiation than the surrounding zirconolite crystals.
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Kusiak, Monika A., Elizaveta Kovaleva, Dennis Vanderliek, Harry Becker, Franziska Wilke, Anja Schreiber, and Richard Wirth. "Nano- and micro-structures in lunar zircon from Apollo 15 and 16 impactites: implications for age interpretations." Contributions to Mineralogy and Petrology 177, no. 12 (November 22, 2022). http://dx.doi.org/10.1007/s00410-022-01977-8.
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AbstractMeteorite impact processes are ubiquitous on the surfaces of rocky and icy bodies in the Solar System, including the Moon. One of the most common accessory minerals, zircon, when shocked, produces specific micro-structures that may become indicative of the age and shock conditions of these impact processes. To better understand the shock mechanisms in zircon from Apollo 15 and 16 impact breccias, we applied transmission electron microscopy (TEM) and studied nano-structures in eight lunar zircons displaying four different morphologies from breccias 15455, 67915, and 67955. Our observations revealed a range of shock-related features in zircon: (1) planar and non-planar fractures, (2) “columnar” zircon rims around baddeleyite cores, (3) granular textured zircon, in most cases with sub-µm-size inclusions of monoclinic ZrO2 (baddeleyite) and cubic ZrO2 (zirconia), (4) silica-rich glass and metal inclusions of FeS and FeNi present at triple junctions in granular zircon and in baddeleyite, (5) inclusions of rutile in shocked baddeleyite, (6) amorphous domains, (7) recrystallized domains. In many grain aggregates, shock-related micro-structures overprint each other, indicating either different stages of a single impact process or multiple impact events. During shock, some zircons were transformed to diaplectic glass (6), and others (7) were completely decomposed into SiO2 and Zr-oxide, evident from the observed round shapes of cubic zirconia and silica-rich glass filling triple junctions of zircon granules. Despite the highly variable effect on textures and Zr phases, shock-related features show no correlation with relatively homogeneous U–Pb or 207Pb/206Pb ages of zircons. Either the shock events occurred very soon after the solidification or recrystallization of the different Zr phases, or the shock events were too brief to result in noticeable Pb loss during shock metamorphism.
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White, Daniela, John C. Parker, and R. Nagarajan. "Mechanistic Investigations of Ruthenium Polishing Enabled by Heterogeneous Catalysis With Titania-based Slurries." MRS Proceedings 1249 (2010). http://dx.doi.org/10.1557/proc-1249-e04-04.
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AbstractDifficulties and challenges have been widely encountered in the chemical mechanical planarization (CMP) of noble metals used as diffusion barrier films due to hardness, chemical inertness and toxic oxidation products, in particular for Ru polishing. A commercial CMC Ru polishing slurry that successfully addressed the safety concerns was based on a high pH (8.4) polymer-treated-alumina-based multi-additive slurry containing complexing reagents (carboxylic acids and salts), corrosion inhibitors, surfactants, and hydrogen peroxide as a mild, non-aggressive oxidizer. Recently, our efforts had been redirected towards the development of a new generation of low pH barrier slurries based on an entirely new concept employing unique Lewis acid type abrasives. This class of materials is well known to be highly reactive in dielectrics polishing (ceria, zirconia, titania), but far less is known about their interactions with Ru, Cu or Ta.In this presentation, we will elaborate the unexpected discovery that hard, chemically inert, noble metals such as ruthenium can be polished easily by virtually abrasive-free and/or oxidizer-free TiO2 based slurries. Of particular importance is the finding that the polymorphic phase of TiO2 (anatase or rutile), its surface chemistry (functional groups, Lewis acid/base character), pH induced surface modification and reactivity, can all mediate the abrasive particle's adsorption properties, catalytic activity and ultimately, its slurry polishing performance.
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Jacinto-Maldonado, Mónica, Diana Meza-Figueroa, Martín Pedroza-Montero, David Lesbarrères, Agustín Robles-Morúa, Sofía Navarro-Espinoza, Belem González-Grijalva, et al. "Mites as a Potential Path for Ce-Ti Exposure of Amphibians." Frontiers in Environmental Science 10 (June 24, 2022). http://dx.doi.org/10.3389/fenvs.2022.870645.
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Despite the documented effects on human and animal health, particles smaller than 0.1 µm in diameter found in soils, sediments, and the atmosphere remain unregulated. Yet, cerium and titanium oxide nanoparticles associated with traffic increase mortality, cause behavioral changes, and inhibit the growth in amphibians. Mites of the genus Hannemania spend their early stages in the soil before becoming exclusive parasites of amphibians. Unlike other mites, Hannemania is found inside the epidermis of amphibians, thus facilitating the intake of particles, and leading to direct and chronic exposure. To better understand this exposure path, we sampled amphibians hosting mites in a river potentially polluted by traffic sources. Particles collected from mites were studied by scanning electron microscopy and Raman spectroscopy while sediment samples were analyzed for total metal content by portable X-ray fluorescence. Our results indicate that sediment samples showed significant correlations between elements (Zr, Mn, Ti, Nb, Fe) often associated with components in catalytic converters and a level of Zr that exceeded the local geochemical background, thus suggesting an anthropic origin. Furthermore, particles adhered to mites exhibited the characteristic Raman vibrational modes of ceria (CeO2, 465 cm−1), ceria-zirconia (CeO2-ZrO2, 149, 251, and 314 cm−1), and rutile (TiO2, 602 cm−1), pointing out to the deterioration of catalytic converters as the most likely source. This research highlights both the importance of unregulated catalytic converters as a source of ultrafine Ce-Ti particle pollution and the role of sub-cutaneous mites as a vector of these particles for amphibian exposure.