Journal articles: 'Zirconium oxide'

1

Fedorov, Pavel P., and Evgeniya G. Yarotskaya. "Zirconium dioxide. Review." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 23, no. 2 (June 4, 2021): 169–87. http://dx.doi.org/10.17308/kcmf.2021.23/3427.

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A review of zirconium dioxide or zirconia ZrO2 is presented. The finding of zirconium compounds in nature, the physical and chemical properties of ZrO2 are given, the polymorphism of zirconium oxide, and the phase diagrams of systems with its participation are considered. The areas of application of zirconia compounds are highlighted: automotive industry, electronics industry, energy and industrial ecology, equipment manufacturing and mechanical engineering the production of zirconium-based refractories, ceramics, enamels, glass, superhard materials, applications in medicine, nuclear energetics, and many others areas of human activity. Cubic modification of zirconium dioxide, stabilized by oxides of rare earth elements,is a jewelry stone (fianite). Partially stabilized zirconium dioxide is a versatile structural material with very high resistance to crack propagation. Solid solutions of REE oxides, especially scandium, have a high oxygen conductivity, which is used in sensors for measuring the partial pressure of oxygen and in fuel cells. Attention is paid to heat-resistant oxide ceramic materials with low thermal conductivity used in the quality of heat-resistant coatings. Considerable attention was paid to the second most important mineral of zirconia - baddeleyite (ZrO2). Baddeleyite is widely used in the production of refractory materials. It is mined for the production of metallic zirconium. The achievements of Soviet and Russian scientists in thedevelopment of technologies for the production of fianite and artificial baddeleyite are presented.

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Arora, Avnish Kumar, and Pankaj Kumar. "Prebiotic studies on the interaction of zirconia nanoparticles and ribose nucleotides and their role in chemical evolution." International Journal of Astrobiology 20, no. 2 (February 26, 2021): 142–49. http://dx.doi.org/10.1017/s1473550421000033.

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AbstractStudies on the interaction of biomolecules with inorganic compounds, mainly mineral surfaces, are of great concern in identifying their role in chemical evolution and origins of life. Metal oxides are the major constituents of earth and earth-like planets. Hence, studies on the interaction of biomolecules with these minerals are the point of concern for the study of the emergence of life on different planets. Zirconium oxide is one of the metal oxides present in earth's crust as it is a part of several types of rocks found in sandy areas such as beaches and riverbeds, e.g. pebbles of baddeleyite. Different metal oxides have been studied for their role in chemical evolution but no studies have been reported about the role of zirconium oxide in chemical evolution and origins of life. Therefore, studies were carried out on the interaction of ribonucleic acid constituents, 5′-CMP (cytidine monophosphate), 5′-UMP (uridine monophosphate), 5′-GMP (guanosine monophosphate) and 5′-AMP (adenosine monophosphate), with zirconium oxide. Synthesized zirconium oxide particles were characterized by using vibrating sample magnetometer, X-Ray Diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy. Zirconia particles were in the nanometre range, from 14 to 27 nm. The interaction of zirconium oxide with ribonucleic acid constituents was performed in the concentration range of 5 × 10−5–300 × 10−5 M. Interaction studies were carried out in three mediums; acidic (pH 4.0), neutral (pH 7.0) and basic (pH 9.0). At neutral pH, maximum interaction was observed. The interaction of zirconium oxide with 5′-UMP was 49.45% and with 5′-CMP 67.98%, while with others it was in between. Interaction studies were Langmurian in nature. Xm and KL values were calculated. Infrared spectral studies of ribonucleotides, metal oxide and ribonucleotide–metal oxide adducts were carried out to find out the interactive sites. It was observed that the nitrogen base and phosphate moiety of ribonucleotides interact with the positive charge surface of metal oxide. SEM was also carried out to study the adsorption. The results of the present study favour the important role of zirconium oxide in concentrating the organic molecules from their dilute aqueous solutions in primeval seas.

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Szawioła-Kirejczyk, Magdalena, Karolina Chmura, Krzysztof Gronkiewicz, Andrzej Gala, Jolanta E. Loster, and Wojciech Ryniewicz. "Adhesive Cementation of Zirconia Based Ceramics-Surface Modification Methods Literature Review." Coatings 12, no. 8 (July 28, 2022): 1067. http://dx.doi.org/10.3390/coatings12081067.

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Introduction: The conditioning procedures for glass-based ceramic restorations before adhesive cementation are generally recognized. In the case of polycrystalline ceramics, which include zirconium oxide, there is still no standardized protocol. The aim of this work was to present conditioning methods of the cementation surface of zirconium oxide fixed dentures. The new generation high translucency zirconia has been also considered. Material and method: The following keywords for the PUBMED and EMBASE databases were used: zirconium oxide, zirconium oxide with increased translucency, bond strength, bending strength, surface treatment. The inclusion criteria were original papers in English published between 2015–2021. Results: Out of 1537 publications, 53 articles were selected for the study, covering methods of conditioning zirconium ceramics, including new materials with increased translucency. These procedures were divided into 5 main groups. Summary: Due to the widespread use of zirconia ceramics and the introduction of new zirconia-based materials, the use of a predictable and standardized cementation protocol is one of the most important factors contributing to the long-term clinical success of prosthetic restorations. Therefore, the research showed differences in the properties of the covered materials after conditioning. It suggests the need to create separate conditioning protocols for highly translucent and traditional zirconia.

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WENDEL, H., H. HOLZSCHUH, H. SUHR, G. ERKER, S. DEHNICKE, and M. MENA. "THIN ZIRCONIUM DIOXIDE AND YTTRIUM OXIDE-STABILIZED ZIRCONIUM DIOXIDE FILMS PREPARED BY PLASMA-CVD." Modern Physics Letters B 04, no. 19 (October 20, 1990): 1215–25. http://dx.doi.org/10.1142/s0217984990001537.

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Thin zirconia (zirconium dioxide) films are deposited by PECVD using as precursors organometallic compounds, metal alkoxides, and metal β-diketonates. The properties of the films depend on the substrate temperature, power density and the nature and partial pressure of the precursor. Thin films of zirconia stabilized with yttria (yttrium oxide) are formed at relatively low deposition temperatures (500°C) using the β-diketones of zirconium and yttrium.

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Al-Hazmi, Mohammed H., YongMan Choi, and Allen W. Apblett. "Preparation of Zirconium Oxide Powder Using Zirconium Carboxylate Precursors." Advances in Physical Chemistry 2014 (December 31, 2014): 1–8. http://dx.doi.org/10.1155/2014/429751.

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Zirconia was prepared at low temperatures (<450°C) using single several source precursors based on zirconium carboxylates where the R groups were systematically varied. The combination of density functional theory (DFT) calculations and extensive characterization of the precursors (i.e., X-ray diffraction, thermal gravimetric analysis, infrared spectroscopy, and scanning electron microscopy) indicated that the carboxylic acid complexes may link the zirconium metal with a cis bidentate configuration. Periodic DFT calculations were performed to examine the interaction between monoclinic ZrO2 and propanoic acid. Dissociative adsorption takes place through the cis bidentate structure with an adsorption energy of −1.43 eV. Calculated vibrational frequencies using the optimized structure are in good agreement with experimental findings.

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Stankovic, Jovan, Slobodan Milonjic, and Slavica Zec. "The influence of chemical and thermal treatment on the point of zero charge of hydrous zirconium oxide." Journal of the Serbian Chemical Society 78, no. 7 (2013): 987–95. http://dx.doi.org/10.2298/jsc121010149s.

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Two zirconia samples were prepared by precipitation from aqueous zirconium oxychloride and zirconil sulphate solutions with potassium hydroxide. The prepared zirconia samples were amorphous. The pHpzc values of zirconia samples, determined from NaCl and NaNO3 solutions, were 6.6 ? 0.1 and 6.9 ? 0.1, respectively. After prolonged hydration of zirconia in doubly distilled water, pHpzc decreased to 4.7 ? 0.3. Crystallization into tetragonal (metastable) + monoclinic zirconia appeared at 691 K. Above 873 K, tetragonal metastable phase changes to monoclinic one. It was shown that crystallite sizes of zirconia treated at 673 - 1273 K increased from 9.5 nm to 40.5 nm, respectively. The increase in temperature from 385 K to 1070 K increased the pHpzc of zirconia samples from 6.6 to 9.0, respectively.

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Hösel, T., Claas Müller, and Holger Reinecke. "Analysis of Surface Reaction Mechanisms on Electrically Non-Conductive Zirconia, Occurring within the Spark Erosion Process Chain." Key Engineering Materials 504-506 (February 2012): 1171–76. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.1171.

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Electrically insulating high performance ceramics like zirconia are increasingly used for high technological applications due to their extraordinary properties. Meanwhile even the spark erosion process can be used to structure non-conductive ceramics by using an assisting electrode (AE). This conductive AE is placed on top of the work piece to enable the process. The electrical contact is sustained during the process by carbonic residua of cracked oil used as a dielectric. For an enhanced understanding of the removal mechanisms during the spark erosion process of such non-conductive ceramics, we analysed the surface of ceramic samples during the entire spark erosion process chain. In our investigation a zirconium oxide with yttrium oxide stabilisation was chosen. For this purpose X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis was performed. The XRD results showed that the zirconium oxide reacts under the presence of carbonic residua during processing into zirconium carbide. This material supports sustaining the conductivity additionally, as it is conductive itself. In a subsequent thermal cleaning step with oxide atmosphere (T = 750°C), remaining carbonic residua are oxidised and thus removed. The XRD measurements after cleaning showed that the zirconium carbide was no longer detectable. Instead a monoclinic zirconium phase was found. This shows that a reverse reaction of zirconium carbide into zirconium oxide took place. To prevent the formation of a non-stabilised monoclinic phase, the oven process was adapted to higher temperatures of 900°C with higher heating and active cooling rates of up to 10 K/s. This adjustment shows that the monoclinic phase can be supressed and the reverse reaction leads to a tetragonal zirconium oxide like the bulk material.

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Nikishina, E. E., E. N. Lebedeva, and D. V. Drobot. "ZIRCONIUM AND HAFNIUM DIOXIDES DOPED BY OXIDES OF YTTRIUM, SCANDIUM AND ERBIUM: NEW METHODS OF SYNTHESIS AND PROPERTIES." Fine Chemical Technologies 13, no. 5 (October 28, 2018): 30–37. http://dx.doi.org/10.32362/2410-6593-2018-13-5-30-37.

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The results of elaborating a method for the synthesis of zirconia and hafnia doped by rare earths (yttrium, erbium and scandium) by using low-hydrated hydroxides of zirconium and hafnium as precursors are reported. The low-hydrated zirconium and hafnium hydroxides were prepared using the heterophase reaction. The physicochemical properties (including sorption properties) of low-hydrated zirconium and hafnium hydroxides ZrxHf1-x(OH)3÷1O0.5÷1.5·0.9÷2.9H2Owere studied. The scheme of thermal decomposition of low-hydrated hydroxides in air was determined. The sorption properties of the low-hydrated hafnium hydroxide are less pronounced owing to the lower amount of sorption centers, in this case, hydroxo and aqua groups. The sequence of stages of thermal decomposition of rare earth acetates was elucidated. Single-phase zirconia and hafnia doped by rare earths (yttrium, erbium and scandium) were obtained. The parameters of the elementary lattice were calculated for each phase. It was established that the stabilization of zirconium dioxide with yttria leads to the formation of interstitial solid solutions based on tetragonal zirconia (in the case of the composition Y2O3×4ZrO2 - cubic modification), with erbium oxide - interstitial solid solutions based on cubic zirconia; with scandium oxide - solid solutions based on tetragonal zirconia. The article presents the results of measuring electrical conductivity.

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Mityushova, Yulia A., Sergey A. Krasikov, Alexey A. Markov, Elmira I. Denisova, and Vadim V. Kartashov. "Effect of a stabilizing additive on the electroconductivity of ZrO2-based ceramics." Butlerov Communications 58, no. 5 (May 31, 2019): 105–9. http://dx.doi.org/10.37952/roi-jbc-01/19-58-5-105.

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The creation of solid oxide fuel cells (SOFC) is one of the promising solutions to the problem of electricity supply. It is advantageous to use stabilized zirconium dioxide (ZrO2) as solid electrolytes in SOFC. In this paper, zirconium dioxide powders with additives of yttrium and scandium oxides (ZrO2–Y2O3, ZrO2–Sc2O3 and ZrO2–Y2O3–Sc2O3) were synthesized. Ceramic samples were obtained from the powders to study the effect of stabilizing additives on the conductive properties of zirconium dioxide. The addition of yttrium oxide Y2O3 in an amount of 8 mol. % contributed to the formation of a solid cubic solution of zirconium dioxide, and scandium oxide Sc2O3 increased the strength and conductive characteristics of the material. The definition of the conductive characteristics was carried out by impedance spectroscopy. Platinum paste was preliminarily applied by printing, which, when measured, ensured contact with the entire surface of the sample under study. It is shown that the addition of yttrium oxide contributes to the formation of a solid cubic solution of zirconium dioxide, and scandium oxide increases the strength (microhardness) and conductive characteristics of the material. Of interest is the simultaneous alloying of zirconium dioxide with scandium and yttrium oxides. The results of determining the properties of ceramic samples showed that the increase in electrical conductivity is more influenced by the addition of Sc2O3 compared with the addition of Y2O3. Stabilization without yttrium oxide leads to unstable conductivity values over time. A sample of ZrO2 – 1 mol%. – Y2O3 – 8 % mol. Sc2O3 has the potential to be used as an electrolyte in solid oxide fuel cells.

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Lin, Cui Hua, Xiong Fei Zhang, Yang Hou, Ya Li Wang, and Gui Wang. "Synthesis of Calcium Oxide Stabilized Cubic Zirconia Powders by Electrochemical Method." Advanced Materials Research 233-235 (May 2011): 2403–8. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.2403.

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Calcium oxide stabilized cubic zirconia powders were synthesized with electrochemical method using analytical reagent zirconium oxychloride and calcium oxide as the raw materials. From XRD analysis, zirconia powders doped calcium oxide are mainly being as cubic phase under the temperature lower than 1100°C. While the zirconia powders which did not doped calcium oxide were transformed from cubic phase to monoclinic phase when the powders were sintered at 750°C. The calcium oxide used as dopant in zirconia has two advantages, the first is that it can stabilize the cubic zircnnia, the second is that it can restrain the zirconia powders’ growing up.

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11

Lugo del Ángel, F. E., R. Silva-Rodrigo, A. Vázquez Rodríguez, R. García Alamilla, J. Navarrete Bolaños, A. Castillo Mares, José Aarón Melo-Banda, Eduardo Térres-Rojas, and J. L. Rivera Armenta. "Studies on the Catalytic Activity of Sulfated Zirconia Promoted with Cerium Oxide." Advanced Materials Research 132 (August 2010): 149–61. http://dx.doi.org/10.4028/www.scientific.net/amr.132.149.

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Pure zirconia, sulfated zirconia and sulfated zirconia modified with 2, 3, 5 and 10 wt. % of cerium oxide were synthesized by sol-gel method. Pt phase was impregnated on the supports using the incipient wet technique. Sulfated zirconium oxide showed tetragonal phase only. Addition of cerium to sulfated zirconia did not modify the tetragonal phase but produced a marked effect on the surface area. Low cerium content may greatly increase the surface area; however, too high cerium content (10 wt.%) may decrease the surface area. Pore size had influence on the catalytic activity and ZrO2 acidity was favored by the sulfate ion incorporation. All catalysts having Brönsted and Lewis acid sites were active in the n-hexane isomerization. The highest n-hexane conversion (40%) and selectivity towards DMB (26%), 2-methyl pentane (61%) and 3-methyl pentane (13%) were reached over the catalyst with 10 wt. % cerium oxide. In addition, sulfated zirconium oxide presented high selectivity of light products (< C6), which indicated that the addition of this doping agent (CeO2) made the catalysts more selective toward the desired reaction products.

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Young, Jay A. "Zirconium(IV) Oxide." Journal of Chemical Education 80, no. 2 (February 2003): 140. http://dx.doi.org/10.1021/ed080p140.

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T.Ch.Taghiyeva, T. Ch Taghiyeva. "X-RAY DIFFRACTION STUDY OF BINARY ZINC-OXIDE CATALYSTS." Azerbaijan Journal of Chemical News 04, no. 01 (May 30, 2022): 60–64. http://dx.doi.org/10.32010/ajcn5012022-60.

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The phase composition of binary zinc-containing catalysts was studied by X-ray diffraction. It was found that the formation of two phases of the initial oxides is observed in all the studied catalytic systems. So, samples of the Zr-Zn-O catalytic system consist of phases of zirconium and zinc oxides, samples of the Ce-Zn-O catalytic system consist of phases of cerium and zinc oxides, while samples of the Mg-Zn-O catalytic system consist of phases of magnesium and zinc oxides. It has been established that the crystallinity of binary zinc-containing catalysts varies in the range from 70% to 89%. Keywords: X-ray phase analysis, binary catalysts, zinc oxide, cerium oxide, zirconium oxide, magnesium oxide

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MOHAMMADI, E., H. ABDIZADEH, H. R. BAHARVANDI, and A. M. HADIAN. "EFFECTS OF CONCENTRATION OF TTIP PRODUCER AGENT ON ZrO2/NANOTiO2 POWDER SYNTHESIS." International Journal of Modern Physics B 22, no. 18n19 (July 30, 2008): 3216–24. http://dx.doi.org/10.1142/s0217979208048139.

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Ceramic materials based on zirconium titanate prepared by sol-gel method are used extensively in microwave, telecommunications and catalysis. In order to investigate the effects of concentration of TTIP, a series of ZrO 2– TiO 2 mixed oxides was prepared by a modified sol–gel method and varying mole fraction of TTIP from 0.002, to 0.1. The samples were characterized by XRD, TG/DTA, and SEM. The XRD pattern of 370°C calcined samples showed the formation of TiO 2 phase. The optimum concentration of TTIP in the zirconia-titania mixed oxide in the precipitation solution was 0.032 for obtaining complete coating. Each oxide was calcined between 250 and 620°C. The results showed that concentration of TTIP have a pronounced effect on particle size of the calcined zirconium titanate ( ZT ) powders. The results showed that the surface area of the composite powder increased proper to monolithic ZrO 2 powder.

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Агарков, Д. А., М. А. Борик, Г. М. Кораблева, А. В. Кулебякин, И. Е. Курицына, Е. Е. Ломонова, Ф. О. Милович, et al. "Влияние термообработки на теплопроводность монокристаллов твердых растворов на основе ZrO-=SUB=-2-=/SUB=-, стабилизированных оксидами скандия и иттрия." Физика твердого тела 62, no. 12 (2020): 2093. http://dx.doi.org/10.21883/ftt.2020.12.50213.160.

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The effect of heat treatment at 1000° C for 400 hours on the thermal conductivity of crystals stabilized with scandium oxide, (ZrO2)1-x(Sc2O3)x (x = 0.08–0.10), and together with scandium and yttrium oxides, (ZrO2)1-x-y(Sc2O3)x(Y2O3)y (x = 0.003−0.20; y = 0.02−0.025). For crystals of zirconium dioxide stabilized with scandium oxide, the most noticeable changes in thermal conductivity concern 9ScSZ crystals, in which changes in the phase composition occur, and a noticeable amount of rhombohedral phase appears. For 8ScSZ crystals, these changes are less noticeable and are mainly caused by the ordering of oxygen vacancies and changes in the microstructure of the samples, while for 10ScSZ crystals they are practically absent. The 10ScSZ crystals have the minimum electrical conductivity, both before and after annealing, which is determined by the highest content of scandium oxide in the solid solution. Small changes in thermal conductivity concern crystals of partially stabilized zirconia codoped with scandium and yttrium oxides. For cubic crystals 8Sc2YSZ and 10Sc2YSZ, there are practically no changes in the value of thermal conductivity, the nature of the temperature dependence of thermal conductivity, and the phase composition of crystals. The introduction of yttrium oxide into solid solutions based on zirconium dioxide along with scandium oxide makes it possible to increase the stability of its phase composition and structurally dependent thermal and electrophysical characteristics.

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Shelekhina, V. M., and M. A. Isupov. "Stabilization of zirconium oxide in aluminum oxide-zirconium oxide system by complex stabilizers." Journal of Engineering Physics and Thermophysics 68, no. 6 (1996): 741–43. http://dx.doi.org/10.1007/bf00855521.

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Ciptasari, Nurhayati Indah, Adri Nora, Lutviasari Nuraini, Lusiana, Nono Darsono, and Muhamad I. Amal. "Effect of Cobalt Content on the Structural Properties of Zirconia Prepared by Sol-Gel Method." Materials Science Forum 1000 (July 2020): 227–32. http://dx.doi.org/10.4028/www.scientific.net/msf.1000.227.

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Zirconia (ZrO2) powders doped with cobalt were prepared by sol-gel method using inorganic salt of zirconium (IV) chloride (ZrCl4) as precursor. The amount of cobalt was varied in the range of 4–16% weight percent to study the effect to structural properties. X-ray diffraction (XRD) analysis suggested the resulting phases were zirconium oxide (Baddeleyite) with monoclinic crystal system along with cobalt oxide as secondary phase. The increasing cobalt content caused the XRD peaks to shift into lower angle due to substitution of Zr atom to smaller Co atom in crystal lattice. Scanning electron microscope (SEM) images showed the samples with higher Co content had smoother surface. Generally, the microstructures of Co doped zirconia powders consisted of large agglomerates with small particles on the surface.

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Frenzel, Nancy, Torsten Otremba, Reinhard Schomäcker, Thorsten Ressler, and Martin Lerch. "Präparation und Charakterisierung von SiO2-geträgerten Zirconiumoxidnitriden mit hoher Oberfläche und Untersuchung ihrer katalytischen Aktivität bei der Ammoniakzersetzung / Synthesis, Characterization, and Catalytic Activity of Zirconium Oxide Nitrides Supported on High-surface SiO2." Zeitschrift für Naturforschung B 66, no. 2 (February 1, 2011): 147–54. http://dx.doi.org/10.1515/znb-2011-0207.

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Zirconium oxide nitrides are active ammonia decomposition catalysts for the production of hydrogen. We present a route to zirconium oxide nitrides with high surface area. The precursor used consisted of a high-surface-area silica material coated with zirconium alkoxide. Subsequent hydrolysis and calcination resulted in ZrO2 supported on SiO2. The high surface area of the material could be maintained in the following ammonolysis procedure leading to the corresponding zirconium oxide nitride. In contrast to the as-prepared ZrO2, the zirconium oxide nitrides exhibited a significant catalytic activity in ammonia decomposition, but compared to an iron oxide-based reference material, the new oxide nitrides showed a rather low activity. Nevertheless, zirconium oxide nitrides constitute suitable model systems for elucidating the effect of nitrogen in the anion substructure on the activity and selectivity of oxide-based ammonia decomposition catalysts.

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Espinoza-González, R. A., D. E. Diaz-Droguett, J. I. Avila, C. A. Gonzalez-Fuentes, and V. M. Fuenzalida. "Hydrothermal growth of zirconia nanobars on zirconium oxide." Materials Letters 65, no. 14 (July 2011): 2121–23. http://dx.doi.org/10.1016/j.matlet.2011.04.056.

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Parise, M., I. Touet, and O. Sicardy. "Oxidation of Zirconium Alloys. Crystallographic Texture of Zirconia: Interpretation and Mechanical Consequences." Textures and Microstructures 30, no. 3-4 (January 1, 1998): 247–63. http://dx.doi.org/10.1155/tsm.30.247.

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In order to have a better knowledge of the mechanical behaviour of the oxide layers growing on zirconium alloys in pressurized water reactors, the textures of different zirconium alloys and their oxide layers are studied. The results show that the texture of the oxide layers present a feature common to all the layers: the tilt angle of the maximum intensities of the pole figures obtained on the layers is almost quite identical for all the studied substrates. The azimuthal reinforcements depend on the metallurgical state of the substrate.The crystallographic direction of monoclinic zirconia common to all the oxide grains is identified. A computation based on mechanical issues is presented: considering the anisotropic elastic properties of the monoclinic monocrystal, it is shown that the particular crystallographic direction is linked to an isotropic state of strains in the plane of the metal–oxide interface.

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Letaief, Sadok, Yun Liu, and Christian Detellier. "Zirconium oxide nanoparticles coated on sepiolite by sol–gel process — Their application as a solvent-free catalyst for condensation reactions." Canadian Journal of Chemistry 89, no. 3 (February 2011): 280–88. http://dx.doi.org/10.1139/v10-142.

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An inorganic nanocomposite made of zirconia nanoparticles coated on the external surfaces of the fibrous clay mineral sepiolite was prepared by using the sol–gel process under soft conditions using zirconium(IV) propoxide in 1-propanol as the precursor. The resulting materials were characterized by X-ray diffraction (XRD), thermal gravimetric analyses (TGA) and differential thermal analyses (DTA), microporosimetry, 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR), and high-resolution transmission electron microscopy (HR-TEM). The organic material from the precursor was fully removed after calcination at 450 °C, concurrently with the crystallization of the cubic phase of zirconium oxide. The coordinated water molecules of sepiolite were fully removed and its symmetrical layered structure was folded after calcination at 650 °C, as observed by XRD and 29Si cross-polarization (CP) / MAS NMR. The arrangement of the nanoparticles of zirconium oxide on the sepiolite external surfaces maintains a fibrous morphology for the nanocomposite. This material was applied as a catalyst for the Knoevenagel condensation reaction of benzaldehyde and malononitrile under solvent-free conditions. Strongly improved yields of reaction, attributed to larger catalytically active surfaces, were obtained compared with either the sepiolite clay mineral or the zirconium oxide tested individually.

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Then, I. K., M. Mujahid, and B. Zhang. "Development of Wear Resistant Zirconium Oxide Thin Films on Stainless Steel Substrates." Materials Science Forum 475-479 (January 2005): 3915–18. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3915.

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The present work deals specifically with the development of zirconium oxide thin film coatings on the stainless steel orthodontic bracket system by sputtering technique. Thin films of zirconium oxide have been deposited on injection molded stainless steel substrates using sputtering under controlled temperature and environment conditions. The deposited films, 1.5 µm in thickness, were found to have a predominantly tetragonal structure with grain size of about 5 nm. The grain size was found to increase only slightly with increasing heat treatment time at 650°C. It has been shown that thin-film zirconia coatings with stable structure and good adhesion along with very low friction coefficient could be produced.

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Watanabe, Keita, Koichi Matsuzawa, Yuu Takeuchi, Kaoru Ikegami, Yoshiro Ohgi, Takaaki Nagai, Ryuji Monden, and Akimitsu Ishihara. "(Digital Presentation) Effect of Iron Doping on Oxygen Reduction Activity of Zirconium Oxides Containing Carbon and Nitrogen Using Pyrazine Carboxylic Acid As Platinum Alternative Cathodes for PEFC." ECS Transactions 109, no. 9 (September 30, 2022): 389–99. http://dx.doi.org/10.1149/10909.0389ecst.

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Fe-added zirconium oxide catalysts were synthesized by using pyrazine carboxylic acid to enhance oxygen reduction reaction (ORR) activity in acidic media. Fe-added zirconium oxide with a Fe/Zr atomic ratio of 0.1 showed highest ORR onset potential, 0.917 V vs. reversible hydrogen electrode among other zirconium oxide-based catalysts including the previous study. High quality active sites for ORR might be created by substitution of Zr4+ by Fe3+ in ZrO2 monoclinic structure. Although no use of carbon support caused a large particle size of zirconium oxides approximately 20~200 nm, the ORR activity drastically increased because of the creation of high quality active sites. We found that a positive correlation between a ratio of ZrO2 monoclinic structure and ORR activity. As a result, the use of pyrazine carboxylic acid was useful to create high quality active sites and a suitable electron conduction path.

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Russak, Michael A., Christopher V. Jahnes, and Eric P. Katz. "Reactive magnetron sputtered zirconium oxide and zirconium silicon oxide thin films." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 7, no. 3 (May 1989): 1248–53. http://dx.doi.org/10.1116/1.576263.

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Bykanova, V. V., V. A. Panasenko, and S. M. Bykanov. "SYNTHESIS AND PHOTOCATALYTIC ACTIVITY OF COATINGS TI/TINOM∙ZrO2 FOR PURIFICATION OF INDUSTRIAL WASTE WATER FROM ORGANIC AROMATIC CONTAMINANTS." Journal of Coal Chemistry 2 (2021): 33–40. http://dx.doi.org/10.31081/1681-309x-2021-0-2-33-40.

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It is shown that photocatalytic processes on semiconductor materials are promising for use in technologies for purifying industrial waste water and air from toxic organic impurities for solving important environmental problems. Studies on the formation of coatings with titanium(IV) oxide supplemented with zirconium(IV) oxide have been carried out. The Ti/TiO2 coverings were formed by anodic oxidation of technical alloys of VT1-0 grade titanium and E-125 zirconium from aqueous electrolyte solutions based on 0.5 M sulfuric acid and 1 M potassium pyrophosphate. To obtain mixed oxide coatings of the Ti/TinOm·ZrO2 composition, zirconium(IV) oxide of a given concentration was additionally introduced into the electrolyte solutions. The photocatalytic activity of the obtained systems was assessed by the phenol oxidation reaction. It is shown that, as a result of anodic oxidation of the VT1-0 alloy in sulfuric and pyrophosphate electrolytes, it is possible to obtain mixed oxide systems of the Ti/TinOm·ZrO2 composition with a porous and microcrystalline surface structure and a zirconium content of up to 2 % by weight. It was found that an increase in the pH of the electrolyte leads to a significant decrease in the content of zirconium in the coatings. It is shown that the contact masses Ti/TiO2, Zr/ZrO2, Ti/TinOm·ZrO2 are photocatalytically active in the oxidation of phenol under the action of UV radiation, and the mixed Ti/TinOm·ZrO2 coatings formed from a sulfuric acid electrolyte exhibit a higher catalytic activity with respect to compared with both individual oxides and Ti/TinOm·ZrO2 deposited from pyrophosphate electrolytes. The results obtained indicate the possibility of creating photocatalytic converters using mixed oxide systems formed on metal supports for purifying wastewater from organic aromatic compounds. Keywords: coatings, titanium(IV) oxide, electrochemical anodizing, photocatalytic activity, zirconium(IV) oxide, organic aromatic pollutants, phenol, waste water, purification. Corresponding author Panasenrj V.A. е-mail: office@niochim.kharkov.ua

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Khatamian, D. "Diffusion of Hydrogen in Single Crystals of Monoclinic-ZrO₂ and Yttrium Stabilized Cubic Zirconia." Defect and Diffusion Forum 297-301 (April 2010): 631–40. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.631.

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Transport of hydrogen through oxide layers formed on zirconium alloys has been the focus of studies associated with hydrogen ingress into nuclear reactor core components. The studies have shown that microstructure and microchemistry of the underlying alloy can affect the characteristics of the oxide and in turn the transport of hydrogen through the oxide and into the underlying metal. In certain cases the oxide layer can be a homogeneous medium for hydrogen diffusion, while in most cases it is found to be heterogeneous and comprised of homogeneous, nonporous and fully oxidized, cells surrounded by a network of fast diffusion paths for hydrogen. Since in such heterogeneous systems the derived diffusion parameter and the cell size are interdependent, an absolute diffusion parameter could only be derived if the cell size were known. However, no such information is available from the microstructural studies on the oxides grown on these alloys. Another alternative is to carry out the measurements in a material, which is homogeneous at least within the dimensions of a few μm - the range of the measurements. With this in mind, hydrogen diffusion measurements were carried out in a set of single crystal zirconia specimens with the prospect that the single crystals would provide a non-porous and homogeneous medium to study the diffusivity of hydrogen. These measurements show that the single crystal specimens, contrary to the initial thinking, are not entirely homogeneous and the results do not yield an absolute diffusion coefficient for hydrogen in zirconium oxides. The details and analyses of the results from the single crystal zirconia specimens are discussed in this paper.

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Muñoz, R. A., J. E. Rodriguez, and Cosme Roberto Moreira Silva. "Study of Polymorphs of Zirconia in the System ZrO₂: ƞ wt% Re₂O₃ Obtained by Polymeric Precursor Method." Materials Science Forum 727-728 (August 2012): 1340–44. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.1340.

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In this paper we propose the stabilization of zirconium oxide with controlled additions of a rare earth elements concentrate, in the system ZrO2: ƞ wt% Re2O3 (withƞ=5.36, 10.47, 13.74, 16.91 e 20) whereRe2O3is a rare earth elements concentrate composed mainly of 76.88% of yttrium oxide, 12.1% of Dysprosium oxide, 4.04% of Erbium oxide and 1.94% of Holmium oxide. The synthesis method used was the Pechini method. The results show that additions of 5.36 and 20 wt% of the concentrate are enough to stabilize the tetragonal and cubic zirconia phases respectively, and that zirconium oxide polymorphs can coexist with additions within these limit. In the characterization of the obtained powders are presented and discussed the following results: differential scanning calorimetry, transmission electron microscopy and X-ray diffraction. Also, it was necessary to make analysis by Rietveld refinement because they had severe overlap in the diffraction peaks. One of the most relevant results is obtaining a raw material, cheap to be used in many technological applications.

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Srinivasan, Ram, Mary B. Harris, Stanley F. Simpson, Robert J. De Angelis, and Burtron H. Davis. "Zirconium oxide crystal phase: The role of the pH and time to attain the final pH for precipitation of the hydrous oxide." Journal of Materials Research 3, no. 4 (August 1988): 787–97. http://dx.doi.org/10.1557/jmr.1988.0787.

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Precipitated hydrous zirconium oxide can be calcined to produce either a monoclinic or tetragonal product. It has been observed that the time taken to attain the final pH of the solution in contact with the precipitate plays a dominant role in determining the crystal structure of the zirconium oxide after calcination at 500 °C. The dependence of crystal structure on the rate of precipitation is observed only in the pH range 7–11. Rapid precipitation in this pH range yields predominately monoclinic zirconia, whereas slow (8 h) precipitation produces the tetragonal phase. At pH of approximately 13.0, only the tetragonal phase is formed from both slowly and rapidly precipitated hydrous oxide. The present results, together with earlier results, show that both the pH of the supernatant liquid and the time taken to attain this pH play dominant roles in determining the crystal structure of zirconia that is formed after calcination of the hydrous oxide. The factors that determine the crystal phase are therefore imparted in a mechanism of precipitation that depends upon the pH, and it is inferred that it is the hydroxyl concentration that is the dominant factor.

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WONG, P. C., Y. S. LI, and K. A. R. MITCHELL. "XPS STUDIES OF THE STABILITY OF A ZIRCONIUM CARBIDE FILM IN THE PRESENCE OF ZIRCONIUM OXIDE AND HYDROGEN." Surface Review and Letters 02, no. 03 (June 1995): 297–303. http://dx.doi.org/10.1142/s0218625x95000315.

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X-ray photoelectron spectroscopy (XPS) has been used to study the interfacial chemistries of a 65-Å film prepared by depositing zirconium in an oxidizing environment onto a methane-pretreated 11-Å thick zirconium oxide film, which initially was deposited onto a gold substrate. The second metal deposition results in an outermost region composed of a mixed zirconium oxide, while below there is metallic zirconium followed by zirconium carbide and carbon on top of the first zirconium oxide film, which is itself in contact with the gold. The carbide component showed no changes on heating to 425°C, on treating with a hydrogen plasma at room temperature, or on heating the resulting film to 425°C. The oxide layers do show characteristic changes, and this also contrasts with earlier observations for a zirconium sulphide film. The zirconium carbide Zr3d 5/2 component has a binding energy of 180.6 eV.

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Chen, H. R., Jian Lin Shi, Jian Hua Gao, L. Li, and D. S. Yan. "Synthesis and Characteristic of Hierarchically Porous Zirconium Oxide Doped with Yttrium." Solid State Phenomena 121-123 (March 2007): 5–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.5.

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A novel and thermally stable hierarchically porous yttrium doped zirconia material with crystallized framework has been synthesized in a facile process. XRD, nitrogen adsorption analysis, FESEM, FETEM, were used for the structural characterizations. This novel hierarchically porous zirconia shows a well-defined ordered macroporous structure, a broad distributed mesoviods, and a very uniform mesoporous pore-distribution. Small amount of yttrium can be helpful to increase the thermal stability of the prepared hierarchically porous zirconium oxide.

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31

Dzhardimalieva, G. I., I. E. Uflyand, V. A. Zhinzhilo, E. G. Drogan, and V. E. Burlakova. "Synthesis of zirconium(IV) oxyacrylate complexes with polypyridine ligands and their use as precursors of nanomaterials with antiwear properties." Perspektivnye Materialy 12 (2022): 62–75. http://dx.doi.org/10.30791/1028-978x-2022-12-62-75.

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In the present work, complexes of zirconium(IV) oxyacrylate with polypyridine ligands 2,2’-bipyridine, 1,10-phenanthroline, and 4’-phenyl-2,2’:6’,2’’-terpyridine were obtained for the first time and characterized by elemental analysis, IR spectroscopy, thermogravimetry and differential scanning calorimetry. Thermolysis of these complexes at 600 °C made it possible to obtain nanosized zirconium oxides, which were studied by X-ray diffraction analysis, scanning electron microscopy, high-resolution transmission electron microscopy, and atomic force microscopy. The average crystallite size of the obtained zirconium oxide nanoparticles is 5.63 – 6.06 nm. Zirconium oxide nanoparticles are characterized by spherical and oval shapes. The products have been tested as anti-wear additives in lubricating oils. The optimal concentrations of nanoparticles were determined, at which the antiwear properties of the lubricant are best manifested.

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Drajewicz, Marcin, Kamil Dychtoń, and Marek Góral. "Thermal Properties of YSZ Powders for Plasma Spraying." Solid State Phenomena 227 (January 2015): 413–16. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.413.

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The oxides in the case of theirs properties are important materials for industrial application especially, in aircraft industry for application as thermal barrier coatings. Thermal properties of zirconium oxide stabilized by yttria are better than other ceramic materials. This powder could be stabilized in room temperature by addition of rare earth elements. In this article the thermal analyses of yttria stabilized zirconia (YSZ) oxide are presented as a baseline for future measurements of thermal properties of YSZ powder with addition of rare earth elements. The thermal expansion, specific heat, thermal diffusivity and thermal conductivity of commercially available Matco 6700 powder offered by Sulzer Metco company were analyzed by thermal methods.

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dos Santos, Demetrio Jackson, Lara Basilio Tavares, and Maria Cecilia Salvadori. "Zirconium Based Metal Pretreatments: A Characterization Method for Ecologically Sustainable Thin Film Surface Pretreatments." Materials Science Forum 869 (August 2016): 693–98. http://dx.doi.org/10.4028/www.scientific.net/msf.869.693.

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Zirconium based metal pretreatments have become widely used in recent years as a substitute for phosphate deposition on steel alloys and for chromate on aluminum alloys in industrial applications. The choice of a zirconium based intermediate layer follows from its ecologic sustainability − decreased water and energy consumption, vehicle weight reduction, and low byproduct generation during processing. Here we describe our investigations of a characterization method of converted metal oxide thin films deposited by a plasma method. The thin film composition was characterized by Rutherford Backscattering Spectroscopy (RBS) and Energy Dispersive Spectroscopy (EDS) before and after conversion by a zirconium-based pretreatment, revealing the formation of zirconia after treatment. The corrosion mechanism of the deposited metal oxide films was investigated using electrochemical analysis, confirming the susceptibility of the film to corrosion and the applicability of corrosion investigations. The results pointed to a better performance of the RBS in comparison to EDS.

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Vaivars, G., Ji Shan, G. Gericke, and V. Linkov. "Phosphorized zirconium oxide nanoparticles." Applied Organometallic Chemistry 19, no. 10 (2005): 1096–100. http://dx.doi.org/10.1002/aoc.978.

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35

Pan, Yaru, Xihui Liang, Zhihao Liang, Rihui Yao, Honglong Ning, Jinyao Zhong, Nanhong Chen, Tian Qiu, Xiaoqin Wei, and Junbiao Peng. "Application of Solution Method to Prepare High Performance Multicomponent Oxide Thin Films." Membranes 12, no. 7 (June 22, 2022): 641. http://dx.doi.org/10.3390/membranes12070641.

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Capacitors play an increasingly important role in hybrid integrated circuits, while the MIM capacitors with high capacitance density and small thickness can meet the needs of high integration. Generally speaking, the films prepared with a single metal oxide dielectric often achieve a breakthrough in one aspect of performance, but dielectric layers are required to be improved to get better performance in leakage current, capacitance density, and transmittance simultaneously in modern electronic devices. Therefore, we optimized the performance of the dielectric layers by using multiple metal oxides. We combined zirconia, yttria, magnesium oxide, alumina, and hafnium oxide with the solution method to find the best combination of these five metal oxides. The physical properties of the multi-component films were measured by atomic force microscopy (AFM), ultraviolet-visible spectrophotometer, and other instruments. The results show that the films prepared by multi-component metal oxides have good transmittance and low roughness. The thicknesses of all films in our experiment are less than 100 nm. Then, metal–insulator–metal (MIM) devices were fabricated. In addition, we characterized the electrical properties of MIM devices. We find that multi-component oxide films can achieve good performances in several aspects. The aluminum-magnesium-yttrium-zirconium-oxide (AMYZOx) group of 0.6 M has the lowest leakage current density, which is 5.03 × 10−8 A/cm2 @ 1.0 MV/cm. The hafnium-magnesium-yttrium-zirconium-oxide (HMYZOx) group of 0.8 M has a maximum capacitance density of 208 nF/cm2. The films with a small thickness and a high capacitance density are very conducive to high integration. Therefore, we believe that multi-component films have potential in the process of dielectric layers and great application prospects in highly integrated electronic devices.

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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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Sokolov, Ilya E., Valery V. Fomichev, Ruslan M. Zakalyukin, Elena V. Kopylova, Andrey S. Kumskov, Rais N. Mozhchil, and Andrey M. Ionov. "SYNTHESIS OF NANOSIZED ZIRCONIUM DIOXIDE, COBALT OXIDE AND RELATED PHASES IN SUPERCRITICAL CO2 FLUID." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, no. 5 (May 13, 2021): 35–43. http://dx.doi.org/10.6060/ivkkt.20216405.6060.

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This study is devoted to obtaining nanoscale zirconium dioxide, cobalt oxide and related phases by SAS method in supercritical carbon dioxide. The synthesized compounds were characterized by a complex of physico-chemical analytical methods: infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy. The experimental parameters for obtaining the nanoparticles were: pressure 10 MPa, temperature 40 °C, carbon dioxide supply rate 35 g/min, the initial solution supply rate 0.5 ml/min. Individual phases containing zirconium and cobalt, and also samples with zirconium to cobalt molar ratios 3:1, 2:1, 1:1, 2:1 and 1:3 were obtained. The use of zirconium and cobalt acetylacetonates as initial components leads to formation of stable products – nanoparticles of acetates of the corresponding metals in the X-ray amorphous state. When heated to 340-350 °C, the destruction of organometallic complexes to oxides occurs with formation of a continuous series of X-ray amorphous solid solutions in the ZrO2-CoO system. At temperatures above 600 °C, the phases crystallize with the decomposition of solid solutions into ZrO2 and Co3O4. When temperature is above 900 °C, further oxidation of cobalt occurs. Thus, cobalt oxide oxidation into Co3O4 proceeds in two steps, at 600 and 900 °C. For samples of zirconium dioxide with cobalt oxide admixture at a temperature of 700 °C stabilization of the cubic modification is observed which is probably due to the entry of cobalt into the cubic structure of zirconium oxide, which prevents transition to tetragonal and monoclinic modifications.

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Jothiramalingam, Rajabathar, Balasubramanian Viswanathan, and Thirukkallam K. Varadarajan. "Zirconium Doped Tunnel Structure Manganese Oxide OMS-2 Catalysts." Eurasian Chemico-Technological Journal 6, no. 2 (July 12, 2017): 117. http://dx.doi.org/10.18321/ectj599.

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Zirconium doped tunnel structure manganese oxide (OMS-2) materials were synthesized by reflux and impregnation methods by adopting suitable synthetic conditions. XRD and TGA analyses were used to<br />characterize the crystal structure and thermal stability of as synthesized zirconium doped manganese oxide OMS-2 catalysts. FT-IR and BET analyses were used to interpret the stretching frequency of corresponding functional group present in the catalysts and surface area of as synthesized catalysts. Fibrous structure and the aggregated particle morphology of zirconium doped manganese oxide OMS-2 catalysts were confirmed by TEM analyses. The synthesized catalysts were tested for liquid phase oxidation of side chain aromatic compounds such as ethyl benzene and benzyl alcohol, TBHP (tert-butyl hydrogen peroxide) as the chemical oxidant. Liquid phase oxidation ethyl benzene over zirconium doped tunnel structure manganese oxide OMS-2 catalysts show the higher substrate conversion compared to that of benzyl alcohol oxidation on as synthesized zirconium doped manganese oxide OMS-2 catalysts.

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Yuvakkumar, R., and Sun Ig Hong. "Baddeleyite Type Monoclinic Zirconium Oxide Nanocrystals Formation." Advanced Materials Research 1102 (May 2015): 79–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1102.79.

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We report successful synthesis of baddeleyite type monoclinic zirconium oxide nanocrystals formation. The product mixture of zirconium incubated at room temperature for 7 days were thoroughly investigated employing X-ray diffraction, Raman spectroscopy and transmission electron microscopy studies. XRD and Raman studies revealed the formation of baddeleyite type monoclinic zirconium oxide nanocrystals. TEM studies revealed the nanocrystal formation with size ranging from 100 nm to 200 nm.

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MIKHAILOVSKAYA, T. P., R. KURMAKYZY, D. K. TOLEMISOVA, and K. A. KADIRBEKOV. "OXIDATIVE AMMONOLYSIS OF 4-METHYLPYRIDINE ON OXIDE VANADIUM-TITANIUM-ZIRCONIUM CATALYST MODIFIED BY TIN AND TUNGSTEN OXIDES." Chemical Journal of Kazakhstan 73, no. 1 (March 14, 2021): 196–203. http://dx.doi.org/10.51580/2021-1/2710-1185.21.

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Catalysts based on vanadium pentoxide modified by Ti, Sn, Zr and W oxides were tested in the oxidative ammonolysis of 4-methylpyridine. The role of the main process parameters such as temperature, the ratio of the initial components in the conversion of the methyl group to the nitrile one, and the optimal conditions for the oxidative ammonolysis of 4-methylpyridine were determined. It is determined that the V-Ti-Zr-O-catalyst and the sample containing 9% of tungsten oxide are superior in catalytic activity to the V-Ti-Zr-Sn-O contact. Conditions that ensure a high selectivity for the formation of 4-cyanopyridine were found. The highest yield of the target product (85-86%) was obtained on V-Ti-Zr-W-O at 270 °C, and the yield of 4-cyanopyridine was 87.5% at 310° C on the V-Ti-Zr-Sn-O catalyst. The phase composition and structural changes occurring in modified vanadium oxide catalysts have been studied. It is determined that mixed V-Ti-Zr-Sn-O and V-Ti-Zr-W-O catalysts contain ZrV2O7, the monoclinic modification of ZrO2 (baddeleyite), TiO2 (anatase), SnO2, WO3, and V2O5. In catalysts, it can exist in small amounts as a separate VO2 phase. The V-Ti-Zr-W-O catalyst showed the best catalytic properties. It has highactivity and selectivity towards 4-cyanopyridine.

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Acosta, D. R., O. Novaro, T. López, and R. Gómez. "Crystalline phases of sol-gel ZrO2 in the ZrO2-SiO2 system: Differential thermal analysis and electron microscopy studies." Journal of Materials Research 10, no. 6 (June 1995): 1397–402. http://dx.doi.org/10.1557/jmr.1995.1397.

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Zirconium oxide dispersed in silica was synthesized by the cogelation of tetraethoxysilane and zirconium acetate. For the gelation, acid and basic media were used. The final zirconia concentration was around 6.7 wt. %. Differential thermal analysis, thermogravimetric analysis, as well as electron microscope techniques were used for the characterization of the samples. It was found that the stabilization of the crystalline phases depends on the preparation conditions and thermal treatments. Tetragonal and monoclinic ZrO2 phases were identified in basic preparations. However, in acidic samples only low-temperature tetragonal phase was identified.

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Zhao, Liang, Shuang Yao, Yong Qiang Li, Zhi Long Zhao, and Qun Hu Xue. "Effects of Calcium Oxide and Magnesium Oxide Stabilizing Agents on the Critical Transformation Size of Tetragonal Zirconia." Materials Science Forum 980 (March 2020): 15–24. http://dx.doi.org/10.4028/www.scientific.net/msf.980.15.

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The preparation of tetragonal zirconia nanopowders by sol–gel method using zirconium oxychloride as raw material, ammonia water and sodium hydroxide solution as precipitant, and calcium oxide or magnesium oxide powders as stabilizing agents is described. After suction filtration, drying, and calcination, tetragonal zirconia nanopowders with different particle size and tetragonal phase content were obtained. The particle size and phase composition of the powders are characterized by using a laser particle size analyzer and an X-ray diffractometer, and the tetragonal phase content and grain size are calculated from the crystal plane formula and Scherrer formula. The analysis of the relationship between the tetragonal phase content and the particle size of the zirconia nanopowders stabilized by calcium oxide and magnesium oxide at room temperature reveals the inhibitory effect of the stabilizing agents on the growth of zirconia grains. The stabilized zirconia nanopowder is finer than unstabilized zirconia nanopowder, and the particle distribution is more uniform in the former. The stabilizing effect of calcium oxide is superior to that of magnesium oxide; the critical transformation size of the zirconia grains stabilized by calcium oxide is the largest, and that of unstabilized zirconia is the smallest. The critical transformation size of calcium oxide-stabilized, magnesium oxide-stabilized, and unstabilized zirconia nanopowders is 18–22.6 nm, 24–28 nm, and 26–33.6 nm, respectively. Under the same calcination condition, the calcium oxide-stabilized zirconia nanopowder retains the highest tetragonal phase content at room temperature.

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Sali, Sanjay K., Narendra K. Kulkarni, Dilip G. Phal, Suresh K. Aggarwal, and Venkatarama Venugopal. "Phase Behavior Studies on Neptunium Oxide-Zirconium Oxide and Neptunium Oxide-Calcia-Stabilized Zirconia Systems." Journal of the American Ceramic Society 93, no. 10 (May 28, 2010): 3437–42. http://dx.doi.org/10.1111/j.1551-2916.2010.03825.x.

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Ciesla, Ulrike, Michael Fröba, Galen Stucky, and Ferdi Schüth. "Highly Ordered Porous Zirconias from Surfactant-Controlled Syntheses: Zirconium Oxide−Sulfate and Zirconium Oxo Phosphate." Chemistry of Materials 11, no. 2 (February 1999): 227–34. http://dx.doi.org/10.1021/cm980205v.

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Wewman, R. A. "Measurement of the Phase Composition of Partially Stabilized Zirconia (PSZ) Test Parts by X-Ray Powder Diffraction." Advances in X-ray Analysis 33 (1989): 467–74. http://dx.doi.org/10.1154/s0376030800019893.

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Zirconia(ZrO2) is one of a number of ceramic materials under development both at Dow and other companies for high cost, low-volume applications under severe corrosion/wear conditions. To improve the physical properties of zirconia, much work has been done worldwide in recent years developing partially stabilized zirconia, or PSZ. This is zirconium oxide which has been “stabilized” in the tetragonal form, typically by the addition of calcium or yttrium oxide. The term “partially stabilized” is given to these materials because the proper amount of oxide stabilizer will cause the zirconia to crystallize almost entirely in the tetragonal form under the proper processing conditions. However, the PSZ fabricated part is not completely stabilized, because it will undergo a tetragonal to monoclinic (T → M) phase transformation when subjected to an applied stress.

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Gerdzhikov, Ivan, Elka Radeva, and Todor Uzunov. "POSSIBILITIES OF IMPROVING THE SHEAR STRENGTH BETWEEN DIFFERENT TYPE OF CEMENT AND ZIRCONIA CERAMICS: LITERATURE REVIEW." Journal of IMAB - Annual Proceeding (Scientific Papers) 27, no. 1 (January 26, 2021): 3557–63. http://dx.doi.org/10.5272/jimab.2021271.3557.

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Background: Zirconia ceramics are a modern dental material which has a wide range of application in restoration of frontal and distal teeth. This is due to its improved mechanical properties and aesthetics. Aim: This literature review analyses the possibilities for improvement of the bond strength between zirconia ceramics and different types of cement which are used for fixation of prosthetic constructions. Review Results: The evidence from the literature indicates that preliminary treatment of zirconia ceramics increases the bond strength significantly to the cement. In this respect, different methods and materials are used for the treatment of the zirconium dioxide surface. Some of them include only mechanical treatment with diamond burs, a different type of lasers and sandblasting with aluminum oxide. Other methods have chemical action by the use of hydrofluoric acid and fluoride compounds. According to some data, zirconium structure does not allow etching which leads to application of different type of primers for increasing the shear strength. Studies show that silane application significantly improves the shear bond strength to the cement, as well as, zirconium tensile strength. Optimal results are registered with a combination of treatment with mechanical methods and silane application. Conclusion: Preliminary mechanical and chemical treatment of zirconia surface improves the shear bond strength considerably to the cement. The variety of surface treatment methods complicates the establishment of a standard protocol for fixation of zirconium prosthetic constructions.

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Shen, Miao, Hao Peng, Min Ge, Chenyang Wang, Yong Zuo, and Leidong Xie. "Chemical interactions between zirconium and free oxide in molten fluorides." RSC Advances 5, no. 51 (2015): 40708–13. http://dx.doi.org/10.1039/c5ra04188k.

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The chemical interactions between zirconium and free oxide in FLiNaK melts at different zirconium to oxide (n_Zr/n_O) molar ratios were studied by means of a carbothermal-reduction technique (LECO oxide analyzer) and Raman spectroscopy.

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Zhang, Jun Song, Chong Sheng Long, Jing Jing Liao, Tian Guo Wei, and Zhong Bo Yang. "Deoxidation Process of Oxidized Zirconium Alloy." Materials Science Forum 993 (May 2020): 22–28. http://dx.doi.org/10.4028/www.scientific.net/msf.993.22.

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When zirconium alloy is corroded, an oxide film is formed on the surface, which hinders the ion transfer during the corrosion process. Therefore, the analysis of the oxide film is an important part of the research on the corrosion resistance of zirconium alloys. In this paper, two kinds of Zr-Sn-Nb alloys were corroded in 400 °C/10.3 MPa pure steam and 500 °C/10.3 MPa pure steam in autoclave to obtain samples with oxide thickness of 14 um and 18 um respectively. Then they were annealed at 800 °C at a pressure of 10-4 Pa for 18 h. XRD and WDS studies were used to analyze the structure and oxygen content of the oxide film after annealing. The results indicate that the oxide films of alloys change from zirconium dioxide to zirconium after annealing. The oxygen diffuses into the substrate and its content decreases continuously with increasing diffusion distance. Combined with the SEM analysis of cross-section samples, it is found that the annealed samples are composed of several layers. An oxygen-saturated zirconium layer, a transitional layer with micro-cracks, an oxygen-dissolved α-Zr layer and a β-Zr layer are identified. Based on these results, the mechanism of the ion transfer in the oxide film during annealing is analyzed deeply. It is proposed that space charges in the oxide film have a major impact on deoxidation kinetics. This study provides a new research method for the corrosion mechanism of zirconium alloys.

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Araki, Wakako, Hiroyuki Norigoe, and Tadaharu Adachi. "Mechanical Properties of Scandia Stabilised Zirconia with Alumina Addition." Key Engineering Materials 385-387 (July 2008): 441–44. http://dx.doi.org/10.4028/www.scientific.net/kem.385-387.441.

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Zirconium oxide doped with scandium oxide is one of the most promising materials for electrolytes of solid oxide fuel cells because of its high ionic conductivity. In this study, temperature dependence of mechanical property, especially strength, of 9 mol% scandia doped zirconia polycrystalline samples with 0 to 30 wt% of alumina additions was examined at temperatures from 293 to 1273 K. Ionic conductivity was also measured by AC impedance analysis. From both mechanical and electrical standpoints, the experimental results were discussed in terms of alumina addition.

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Nesamani, I. Flavia Princess, V. Lakshmi Prabha, Aswathy Paul, and D. Nirmal. "Synthesis and Dielectric Studies of Monoclinic Nanosized Zirconia." Advances in Condensed Matter Physics 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/828492.

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Zirconium dioxide is a prospective high-κmaterial that can replace silicon dioxide. Zirconium dioxide nanoparticle has been synthesized using sol-gel process at room temperature. The structural and morphological characterization of the nanoscaled zirconium dioxide is done using FTIR, SEM, X-ray diffraction, and TEM. The particle size of the synthesized ZrO2is observed in the range of 50–80 nm with an average crystallite size of 2–10 nm. The results are compared with commercial coarse zirconia which showed a particle size in the range of 900 nm–2.13 µm and crystallite size of 5.3 nm–20 nm. It is expected that both nanoscaling and the high dielectric constant of ZrO2would be useful in replacing the low-κSiO2dielectric with high-κZrO2for CMOS fabrication technology. The synthesized ZrO2is subjected to impedance analysis and it exhibited a dielectric constant of 25 to find its application in short channel devices like multiple gate FinFETS and as a suitable alternative for the conventional gate oxide dielectric SiO2with dielectric value of 3.9, which cannot survive the challenge of an end of oxide thickness ≤ 1 nm.

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Journal articles on the topic 'Zirconium oxide'

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