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Journal articles on the topic 'CHROMIUM OXIDES'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Cochran, SJ, and FP Larkins. "An X-Ray Photoelectron Study of Doped and Supported Nickel Oxide." Australian Journal of Chemistry 38, no. 9 (1985): 1293. http://dx.doi.org/10.1071/ch9851293.

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The surfaces of lithium-and chromium-doped nickel oxide and of nickel oxide supported on alumina have been examined by X-ray photoelectron spectroscopy. The concentration of the nickel(III) species increased for the lithium-doped oxide and decreased for the chromium-doped oxide relative to the undoped oxide. The effects of doping were manifested most clearly however by the amount of oxygen-containing species adsorbed on the oxide surface rather than by variations in the nickel(III) peak intensity. Lithium-doped oxides were also shown to reduce more readily than undoped or chromium-doped oxides in the presence of carbon-containing impurities. The rate of reduction is influenced by the activation energy for electron transport which is related to the availability of the nickel(III) species. Supported oxides showed significant surface enhancement of nickel(II) as well as an absence of the nickel(III) species. The nickel(II) species in the supported oxide was not easily reduced to nickel(0).

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2

Davies, T. J., M. Biedermann, Q.-G. Chen, H. G. Emblem, and W. A. Al-Douri. "Refractory oxides containing aluminium and barium." Cerâmica 44, no. 289 (October 1998): 177–82. http://dx.doi.org/10.1590/s0366-69131998000500005.

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Oxides containing aluminium and barium, optionally with chromium, are refractory with several possible industrial uses. A gel precursor of an oxide having the formula BaO.n(Al2xCr2yO3), where 1<n<6.6, (x+y)=1 and 0<y<0.5 was prepared by mixing a solution of a barium salt with a solution of an aluminium salt or a solution of an aluminium salt and a chromium III salt, then forming a gel which was fired to obtain the desired oxide. Filaments may be drawn as the gel is forming or extruded from a semi-rigid gel. FT-lR, XRD and 27Al NMR studies showed that barium is not incorporated directly into the gel structure. Barium aluminium oxides were obtained only after liquefaction of barium species. A powder mixture suitable for firing to an oxide of the formula BaO.m [Al2xCr2y O3] where 4.6<m<6.6, (x+y)=1 and 0<y<0.5 was prepared from source materials barium hydroxide, barium oxide, barium carbonate and barium mono-aluminate, alumina and/or a hydrated alumina and chromium III oxide, the relative amounts being varied to give the desired values of m and y on firing. A preferred oxide has the formula BaO.6Al2O3 (m=6 and y=0). Strong ceramic shapes have been prepared from this. XRD studies of oxide compositions (n or m=6 and y=0) sintered at high temperature showed that barium mono-aluminate is a low-temperature intermediate phase. Chromium III reduces the temperature required to form a barium aluminium oxide. Previously published work is summarised.

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3

Gac, Wojciech, Witold Zawadzki, Grzegorz Słowik, Magdalena Greluk, Justyna Pawlonka, and Andrzej Machocki. "Chromium-modified zinc oxides." Journal of Thermal Analysis and Calorimetry 125, no. 3 (June 18, 2016): 1205–15. http://dx.doi.org/10.1007/s10973-016-5586-4.

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4

Arora, Pankaj. "Chromium Oxides and Lithiated Chromium Oxides. Promising Cathode Materials for Secondary Lithium Batteries." Electrochemical and Solid-State Letters 1, no. 6 (1999): 249. http://dx.doi.org/10.1149/1.1390702.

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5

JIANG, ZHI, HAIRONG ZHANG, ZHONGPENG WANG, MINGXIA CHEN, and WENFENG SHANGGUAN. "SIMULTANEOUSLY CATALYTIC REMOVAL OF NOx AND SOOT ON RARE EARTH ELEMENT OXIDE LOADED WITH POTASSIUM AND TRANSITION NANOSIZED METAL OXIDES." Nano 03, no. 04 (August 2008): 239–44. http://dx.doi.org/10.1142/s1793292008001088.

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The simultaneous catalytic removal of NO x and soot over the rare earth element (REE) oxide-based mixture oxides loaded with potassium and transition nanosized metal oxide (designated as M/K/REE oxide) was investigated by using temperature-programmed reaction (TPR). The influence of the type of REE oxides together with the type and amount of transitional metal oxides on the catalytic removal activity was discussed. K / Nd 2 O 3 was found to be the most active oxide among the REE oxides to simultaneous remove the NO x and soot under lean conditions. Chromium oxide was more active than the other transition metal oxides on enhancing the activity of soot oxidation of Nd 2 O 3 loaded with potassium. The optimum loading level of chromium was about 10 wt%, with ignition temperature at about 237°C and the conversion ratio NO → N 2 about 24.1%. The Mn -loading on K / Nd 2 O 3 resulted in the biggest conversion efficiency of NO to N 2 at about 30.2%. The increasing catalytic reaction of NO x–soot activities is attributed to the formation of complex crystalline phase in the catalyst together with the improving contacting between catalysts and soot.

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6

Shaporova, E. A., A. A. Zhukova, A. K. Baev, and A. Yu Sidorenko. "Acid-basic properties of chromium(III) oxide surface." Proceedings of the National Academy of Sciences of Belarus, Chemical Series 57, no. 3 (September 5, 2021): 270–77. http://dx.doi.org/10.29235/1561-8331-2021-57-3-270-277.

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The article is devoted to the study of the nature and number of acid-base centers on the surface of chromium(III) oxide obtained by precipitation from an aqueous nitrate solution. The curve of the distribution of the number of acidbase centers of the samples is plotted depending on the indicator of the ionization constant of indicators. It was determined that the main Lewis centers make the main contribution to the acidity of the samples; there are also Bronsted centers of different acidity. A comparative analysis of the structural features of the surface of oxides of chromium, zinc and binary systems Cr (III)–Zn (II) was carried out according to the results of X-ray phase analysis of oxides and thermolysis of the corresponding hydroxides. Based on this, the possibility of obtaining nanosized catalysts based on oxide-hydroxide systems of chromium with a number of 3d-metals obtained in the process of polynuclear hydroxocomplexation is predicted.

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7

CROSBIE, G. M., G. J. TENNENHOUSE, R. P. TISCHER, and H. S. WROBLOWA. "Electronically Conducting Doped Chromium Oxides." Journal of the American Ceramic Society 67, no. 7 (October 4, 2006): 498–503. http://dx.doi.org/10.1111/j.1151-2916.1984.tb19642.x.

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8

Zachariasz, R., D. Bochenek, and B. Bruś. "Internal Friction In The PFN Ceramics With Chromium Dopand." Archives of Metallurgy and Materials 60, no. 3 (September 1, 2015): 1773–76. http://dx.doi.org/10.1515/amm-2015-0302.

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Abstract An aim of this work was to determine an influence of an admixture, the chromium (for x from 0.01 to 0.06), on the mechanical properties of the PFN ceramics. The ceramics with chemical composition Pb(Fe0.5−xCrxNb0.5)O3 was synthesized in two steps from simple oxides PbO, Fe2O3, Nb2O5, Cr2O3. The first stage was based on obtaining the FeNbO4 from the Fe2O3 and Nb2O5 simple oxides. At this stage an admixture in a form the Cr2O3 chromium oxide was added to the solution. In the second stage the PbO lead oxide and the doped FeNbO4 (obtained earlier) were synthetized. The sintering of ceramic samples PFCN type was carried out by free sintering method. Temperature measurements of the internal friction were conducted on a computer-controlled automatic resonant mechanical spectrometer (heating cycle with 3 deg/min).

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9

Rebak, Raul B., Michael Larsen, and Young-Jin Kim. "Characterization of oxides formed on iron-chromium-aluminum alloy in simulated light water reactor environments." Corrosion Reviews 35, no. 3 (August 28, 2017): 177–88. http://dx.doi.org/10.1515/corrrev-2017-0011.

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AbstractTo avoid accidents like that in Fukushima, the US Department of Energy is engaged with a nuclear fuel vendor to evaluate the performance of iron-chromium-aluminum (FeCrAl) alloys such as advanced powder metallurgy tubing (APMT) as accident-tolerant material for uranium dioxide fuel cladding in light water reactors (LWR). It was important to characterize the oxides formed on APMT under both boiling water reactor (BWR) and pressurized water reactor (PWR) environments for a better understanding of its environmental sustainability in LWRs. Coupons of APMT were exposed for 1 year to both hydrogenated and oxygenated high-purity water at 288°C (e.g. simulated BWR water chemistry without Pt injection) and hydrogenated high-purity water at 330°C (e.g. simulated primary PWR water chemistry without Li/B addition). Results show that after 1-year immersion, APMT always developed a chromium-rich protective oxide film on its surface. In oxygen-containing environments, the oxide consisted of a dual layer, an external thicker layer containing mostly iron oxides and a thinner internal layer rich in chromium oxide. In hydrogen environments, only a single oxide layer formed, consisting of chromium oxide. This is a similar finding as for type 304 and 316 stainless steels and for nickel-based alloy 600, which is extensively reported in the literature. General corrosion of APMT alloys under LWR operating conditions would not be a limiting factor for its performance as cladding material.

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10

Arora, Pankaj, Dong Zhang, Branko N. Popov, and Ralph E. White. "ChemInform Abstract: Chromium Oxides and Lithiated Chromium Oxides. Promising Cathode Materials for Secondary Lithium Batteries." ChemInform 30, no. 7 (June 17, 2010): no. http://dx.doi.org/10.1002/chin.199907012.

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11

Ortiz-Morales, Martin, Juan Jose Soto-Bernal, Claudio Frausto-Reyes, Sofia E. Acosta-Ortiz, Rosario Gonzalez-Mota, and Iliana Rosales-Candelas. "Multiwavelength Raman Spectroscopic Analysis of Superficial Iron–Chromium Oxides Generated Using Laser Irradiation." Applied Spectroscopy 72, no. 6 (February 14, 2018): 879–85. http://dx.doi.org/10.1177/0003702818758325.

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In order to characterize iron–chromium oxides generated by laser irradiation on the surface of stainless steel plates, an ultraviolet–visible (UV-Vis) near-infrared (NIR) multiwavelength excitation Raman analysis has been performed using both austenitic SS304 and ferritic SS430 stainless steel samples. Raman spectra were obtained using five different excitation wavelengths from blue (455 nm) to NIR (830 nm). These measurements have allowed us to observe and identify four Raman bands, among which two have not been previously observed for iron–chromium oxides, and characterize the existence of different resonant excitation conditions for the different excitation wavelengths. For example, when using 455 nm as excitation wavelength the band at 485 cm−1 did not show up, although that when using 830 nm as excitation wavelength is a clear characteristic band for iron–chromium oxide. In addition, the dependence of the spectra profile with the excitation wavelength for films and microspheres features was observed. This experimental Raman analysis shows the importance of the excitation wavelength for the characterization of metallic oxides with different features.

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12

Cai, Yangchuan, Zhen Luo, Zunyue Huang, and Yida Zeng. "Influence of Oxides on Microstructures and Mechanical Properties of High-Strength Steel Weld Joint." High Temperature Materials and Processes 35, no. 10 (November 1, 2016): 1047–53. http://dx.doi.org/10.1515/htmp-2015-0151.

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AbstractA comprehensive investigation was conducted into the effect of oxides on penetrations, microstructures and mechanical properties of BS700MC super steel weld bead. Boron oxide changed the penetration of weld bead by changing the Marangoni convection in the weld pool and contracting the welding arc. Chromium oxide only changed the Marangoni convection in the weld pool to increase the penetration of super steel. Thus, the super steel weld bead has higher penetration coated with flux boron oxide than that coated with chromium oxide. In other words, the activating flux TIG (A-TIG) welding with flux boron oxide has less welding heat input than the A-TIG welding with flux chromium oxide. As a result, on the one hand, there existed more fine and homogeneous acicular ferrites in the microstructure of welding heat-affected zone when the super steel was welded by A-TIG with flux boron oxide. Thus, the weld beads have higher value of low-temperature impact toughness. On the other hand, the softening degree of welding heat-affected zone, welded by A-TIG with flux boron oxide, will be decreased for the minimum value of welding heat input.

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13

Voleník, K., J. Lettner, F. Hanousek, J. Dubsky, and B. Kolman. "Oxides in plasma-sprayed chromium steel." Journal of Thermal Spray Technology 6, no. 3 (September 1997): 327–34. http://dx.doi.org/10.1007/s11666-997-0067-8.

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14

Li, Huaying, and Aichun Zhao. "Pickling Behavior of Duplex Stainless Steel 2205 in Hydrochloric Acid Solution." Advances in Materials Science and Engineering 2019 (February 25, 2019): 1–6. http://dx.doi.org/10.1155/2019/9754528.

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The oxide-scale structure and pickling behavior of oxided 2205 duplex stainless steel in the electrolytes containing hydrochloric acid were investigated. The oxide scales mainly consist of two layers: the outer layer is dense Fe2O3, and the inner granular is FeCr2O4 spinel. During the pickling process, pittings form around the boundaries of FeCr2O4 particles or interfaces of two kinds of oxides, which results in that the electrolyte can directly react with the chromium-depleted layer along the pittings to produce an “undercut” effect so that the pickling efficiency is improved markedly. The pickling mechanism was discussed, and the model was established.

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15

Wiengmoon, Amporn, Jeerapat Nakpratum, Torranin Chairuangsri, and John T. H. Pearce. "Oxidation Behavior of 30wt.%Cr-3.75wt.%V High Chromium Cast Iron." Key Engineering Materials 675-676 (January 2016): 581–84. http://dx.doi.org/10.4028/www.scientific.net/kem.675-676.581.

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This work focuses on the oxidation behavior of 2.4wt.%C-30wt.%Cr-3.75wt.%V cast iron in air at 1000 °C for 1-48 h with weight gain measurements taken at different times. The oxidized surfaces and cross sections were characterized by XRD, OM, SEM and EDS. It was found that the as-cast microstructure consisted of a ferritic matrix and M7C3 carbide. The surface oxide scale consisted of multi-oxides and the grain size of the oxides increased with increasing holding times. XRD and SEM-EDS results revealed that the multi-oxide layer can be Cr2O3, (Fe,Cr,V)2O3 and SiO2. After about 48 h, a continuous SiO2 inner-layer was observed and the oxide scale tended to swell, contained pores, and became detached from the surface because of its poor adherence.

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16

Gutiérrez, Juliana, Gabriel Plascencia, Antonio Romero, Fidel Reyes, and Isaac Arellano. "Rate of Reduction of Chromium Oxides in a Slag by FeSi and FeMgSi Ferroalloys." Defect and Diffusion Forum 258-260 (October 2006): 288–93. http://dx.doi.org/10.4028/www.scientific.net/ddf.258-260.288.

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The rate of reduction of chromium oxides in a stainless steel slag was studied in stagnant slag / metal melts at 1600 °C. The experimental results show that the magnesium contained in a FeMgSi ferroalloy has a reduction potential comparable to that of the silicon in a FeSi ferroalloy. On the other hand, it was confirmed that the rate limiting step in the reduction of the chromium oxides is the transport of chromium from the bulk of the slag to the slag / metal interface. The mass transfer coefficients for the reduction of chromium were estimated and are in good agreement with previously reported values.

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17

Gonzales, Sébastien, Lucile Combarmond, Minh Thi Tran, Yves Wouters, and Alain Galerie. "Short Term Oxidation of Stainless Steels during Final Annealing." Materials Science Forum 595-598 (September 2008): 601–10. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.601.

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Two ferritic AISI 430 and AISI 441 and two austenitic AISI 304 and AISI 316L stainless steels were submitted to short term oxidation in a complex atmosphere 3% O2, 16% H2O, 8% CO2, 73% N2 to simulate phenomena occurring during the rapid furnace annealing taking place after the final cold rolling. This thermal sequence is devoted to metallurgical aims but generates undesirable oxides which have to be further pickled. Temperature of the furnace was set to the values used in industrial practice: 900°C for 430, 1060°C for 441 and 1120°C for both austenitics. Six different oxidation durations were used between 30 and 300 s. For the shortest times, sample temperature was not constant and heating rate depended on sample thickness. Oxide thickness measured by GDOS was shown to increase monotonically for all grades whereas mass change measurements exhibited initial mass losses for the austenitic grades. XRD and Raman spectroscopy were used for phase characterisation and confirmed the increase of the ratio chromia/haematite with increasing annealing time. Enrichment of manganese (MnCr2O4), silicon (SiO2) and boron (B-containing oxide) at the external (Mn) and internal (Si, B) interfaces was observed on the GDOS profiles (boron for austenitic grades only). Manganese spinel was responsible for blocking chromium (VI) volatilisation after a certain time, and interface oxides for hindering chromium transfer from the steel to the oxide scale. Ferritic grades behaved the same, except that no boron enrichment was detected. Besides, stabilised 441 exhibited Ti and Nb enrichments as oxides at both internal and external interfaces. External TiO2-NbO2 solid solution was assumed to be hardly dissolved in acidic pickling baths. All these results were consistent with the different pickling behaviours of the materials.

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18

Atasoy, Ahmet, and F. R. Sale. "An Investigation on the Solid State Reduction of Chromite Concentrate." Solid State Phenomena 147-149 (January 2009): 752–57. http://dx.doi.org/10.4028/www.scientific.net/ssp.147-149.752.

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In this article, Turkish chromite concentrate was reduced with metallurgical coke at temperature between 1000-1500 °C with variables reducing times. The reduction mechanism and the microstructure of the reduced chromite were investigated. There were closer relationships between the reduction of chromite and the sample morphology, such as, the surface area and the porosities and cracks of the particle have positive effect on the metallization of iron and chromium oxides. The reduction of the iron chromite spinel started at 1000 °C, but picrochromite started to reduce at temperature around 1300 °C. At lower temperature, the formation of iron carbide phases was affected on the formation of ferro alloy and accelerates the reduction of chromium. The formation of carbon monoxide was also affected on the reduction of chromite spinel, especially around imperfections of grain where porosity, cracks and fractures act as diffusion channel for the reducing gas. For the charecterisation of the reaction products, X-ray diffraction techniques, SEM and EDAX were used.

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19

MOON, SANGWOON, BOKLAE CHO, SUKMIN CHUNG, CHONGDO PARK, KIJEONG KIM, TAIHEE KANG, and BONGSOO KIM. "THE OPTIMAL FORMATION CONDITION OF CHROMIUM OXIDE THIN FILM ON STAINLESS-STEEL SURFACE." Surface Review and Letters 09, no. 01 (February 2002): 285–91. http://dx.doi.org/10.1142/s0218625x02002208.

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We investigated the various oxidation conditions of stainless-steel surface using synchrotron radiation photoemission spectroscopy. Stainless-steel samples are oxidized at 450–550°C in various oxygen partial pressures. Increasing the annealing temperature from 450°C to 550°C, the trivalent chromium concentration in the surface increased and iron oxides decreased. The PES spectra from stainless steels oxidized at 550°C show that there exists the critical oxygen partial pressure, [Formula: see text] Torr. Below this critical pressure, the oxide formed mainly consists of chromium oxide, while the oxide formed mainly consists of iron oxide above the critical pressure. The oxidation behavior is in good agreement with the Ellingham diagram (a free-energy/temperature diagram).

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20

Mukashev, N. Zh, N. Y. Kosdauletov, and B. T. Suleimen. "Comparison of Iron and Chromium Reduction from Chrome Ore Concentrates by Solid Carbon and Carbon Monoxide." Solid State Phenomena 299 (January 2020): 1152–57. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.1152.

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The possibility of reduction of chromium and iron from complex oxides by gaseous carbon monoxide and solid carbon was investigated. The chromium ore concentrates of Kempirsai and Aganozero deposits used in present study had different ratio of iron and chromium content. The Reduction in CO gas atmosphere did not result in reduction of chromium and iron from spinels; however, it resulted in reduction of fines from the drying apparatus, where the particles of coke presented along with the particles of the Kempersai chromite. At the same time, iron and nickel were reduced from the silicates of the gangue minerals. In the samples mixed with solid carbon a continuous layer of carbides formed on the surface of the spinel grains. The formation of a continuous shell retarded and practically stopped the reduction process. The further development of reduction was possible after destruction of the shell that occurred as a result of smelting of the carbides and silicides mixture that constitute the shell.

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21

Kanapinov, M. S., G. M. Kashkarov, O. A. Lebedeva, T. V. Novoselova, N. P. Tubalov, and O. V. Yakovleva. "Metal-ceramic permeable SHS-materials based on alloy-steel scale and ilmenite for cleaning exhaust gases of diesel engines." NOVYE OGNEUPORY (NEW REFRACTORIES) 1, no. 5 (October 27, 2019): 112–16. http://dx.doi.org/10.17073/1683-4518-2019-5-112-116.

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The possibilities of obtaining porous permeable cermet SHS-materials with catalytic properties are studied. The mixture consisted of powders of steel alloy scale, concentrate of ilmenite, oxides of aluminum or chromium, the basis of the material formed the backbone of metal ceramics (Al2O3) and reduced iron, as well as additives of metal oxides. The resulting material is intended for the catalytic purification of exhaust gases of diesel engines, in particular, from nitrous oxide, carbon monoxide and soot.

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22

Oros, C., Anurat Wisitsoraat, Pichet Limsuwan, M. Horpathum, V. Patthanasettakul, and Adisorn Tuantranont. "Gas-Sensing Property Evaluation of Reactively Sputtered Chromium Oxide Thin Films." Advanced Materials Research 55-57 (August 2008): 285–88. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.285.

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Metal oxide thin film materials, including SnO2, TiO2, WO3, MoO3, ZnO, have been widely studied for gas sensing applications. However, new gas-sensing materials with distinct and diverse characteristics for new sensing applications such as electronic nose are still being explored. Presently, gas sensing properties of other metal oxides have not yet been extensively explored. Chromium oxide is an interesting metal oxide for gas sensor because of its temperature stability and moderate electrical conductivity. Nevertheless, there have been very few studies on gas sensing behaviors of this material. In this work, chromium oxide thin films were systematically studied by reactive sputtering with varying sputtering parameter including oxygen flow rate. Structural characterization by means of scanning electron microscopy and X-ray diffraction reveals that the films have sub-micometer grain-size with Rhombohedral phase of Cr2O3. Gas-sensing performances of sputtered chromium oxide thin film have been characterized toward ethanol and acetylene sensing. It was found that chromium oxide thin films exhibit p-type conductivity with increased resistance when exposed to ethanol and acetylene, which are reducing gases. In addition, sensitivity to both acetylene and ethanol tend to improve as oxygen flow rate increases. Furthermore, the chromium oxide thin films exhibit high sensitivity at moderate temperature of 250-300 °C with minimum operating temperature of 200 °C.

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23

Sun, Bin, Shou Ren Wang, Yan Jun Wang, and Yong Zhi Pan. "Isothermal Oxidation Behavior of the AISI430 Stainless Steel at High Temperature in Static Air." Advanced Materials Research 306-307 (August 2011): 95–99. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.95.

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Isothermal oxidation behavior of the AISI430 stainless steel was investigated at 900°C and 950°C in air. Isothermal themogravimettric analyses were performed at high-temperature for 360ks (kilo-seconds). The microstructures of the oxide films on the stainless steel were characterized by SEM and chemical analyses were performed by EDS and X-ray diffraction. The oxide film included outer layer and inner one. The outer layer was magnetite and hematite oxides with no significant amounts of chromium and the inner one was formed by iron and chromium spinel. Significantly accelerated and anomalous oxidation was observed with the stainless steel AISI430 in air at 900°C.

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24

Birchall, Thomas, Christopher Hallett, Ann Vaillancourt, and Krzysztof Ruebenbauer. "A study of iron–tungsten oxides and iron–chromium–tungsten oxides." Canadian Journal of Chemistry 66, no. 4 (April 1, 1988): 698–702. http://dx.doi.org/10.1139/v88-121.

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A 57Fe Moessbauer study of the Fe2O3–WO3 and Fe2O3–Cr2O3–WO3 systems has been carried out. Single phase materials could be prepared having the composition Fe2−xWO6−3x/2 (x = 0.28), the stoichiometric Fe2WO6 always contained detectable amounts of α-Fe2O3. The iron tungstates are found to be unstable to prolonged heating at 1000 °C. The Cr2−yFeyWO6 (0 < y ≤ 2) system was shown to be of the trirutile type when y ≤ 1.7 but multiphasic when y ≥ 1.7, these latter phases have structures based upon the iron and chromium tungstate phases, respectively. The Moessbauer parameters for the Cr2−xFeyWO6 compositions do not appear to behave in the same fashion as the related Fe2−xCrxTeO6 system.

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25

Jeong, Y. U. "Amorphous Ruthenium-Chromium Oxides for Electrochemical Capacitors." Electrochemical and Solid-State Letters 3, no. 5 (1999): 205. http://dx.doi.org/10.1149/1.1391003.

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26

Hild, M., K. Kaeser, G. Piller, and H. Schneuwly. "Capture of negative muons in chromium oxides." Journal of Physics B: Atomic and Molecular Physics 18, no. 10 (May 28, 1985): 2093–104. http://dx.doi.org/10.1088/0022-3700/18/10/023.

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27

Morpurgo, Simone, Mariano Lo Jacono, and Piero Porta. "Copper—zinc—cobalt—chromium hydroxycarbonates and oxides." Journal of Solid State Chemistry 119, no. 2 (November 1995): 246–53. http://dx.doi.org/10.1016/0022-4596(95)80038-q.

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28

Vashkevich, Fedor, Dmytro Laukhin, Mykhailo Spilnyk, Vladimir Zhuravel, and Alexey Zagorodni. "Researh of Influence of Technological Factors of Formation of Plasma Coatings on their Thermal Technical Properties." Key Engineering Materials 844 (May 2020): 188–93. http://dx.doi.org/10.4028/www.scientific.net/kem.844.188.

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The article considers issues related to the choice of abrasive material and technology of its use for the formation of necessary roughness on the base material and necessary heat resistance of the heat-protective coating during plasma spraying. The influence of the shape and size of the abrasive on final roughness of the treated surface was studied at various angles of contact between the sprayed abrasive and the surface (angle of attack). From the condition of maximum heat resistance, the composition of the heat-resistant composite coating of the spinel type was determined, which consists of 3 layers: the 1st layer (sublayer) material is a chromium-aluminum composite and the 2nd layer of a transitional spinel-based aluminum and chromium oxide + chromium-aluminum composite and the 3rd a layer of spinel based on aluminum and chromium oxides.

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29

Dehmani, Younes, and Sadik Abouarnadasse. "Total Oxidation of Isopropanol in the Liquid Phase, under Atmospheric Pressure and Low Temperature, on Transition Metal Oxides Catalysts Cr2O3 and Fe2O3." Journal of Chemistry 2020 (July 13, 2020): 1–8. http://dx.doi.org/10.1155/2020/6129526.

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Isopropanol oxidation in the liquid phase under atmospheric pressure and low temperature has been studied in the presence of transition metal oxides (Cr2O3 and Fe2O3) prepared by the precipitation method. These solids characterized by structural analyses (FTIR and XRD) and textural analysis (BET) have led to results in line with those reported in the literature. Chromium oxide has a much more developed texture, with a specific surface area and pore volume 5 times larger than iron oxide. Both of the solids show a good specific activity and led to acetone and carbon dioxide to be formed as the only oxidation products of isopropanol. However, chromium oxide is more active. The initial catalytic activity for the latter is varying between 4.87 ∗ 10−6 and 5.79 ∗ 10−6 mol·g−1·s−1 with temperature range from 40 to 80°C. Kinetic study shows that the reaction follows a successive scheme: isopropanol ⟶ acetone ⟶ CO2 involving a redox mechanism. The low value of the activation apparent energy (Ea.(Cr2O3) = 2.87 kJ·mol−1 < Ea. (Fe2O3) = 5.37 kJ·mol−1) justifies the relatively higher activity observed for chromium oxide.

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Mammadova, S. H., and A. A. Ahmadova. "DEPENDENCE OF Cr-Cu-O CATALYSTS ACTIVITY IN THE REACTION OF ETHANOL DEHYDROGENATION ON THEIR PHASE COMPOSITION." Chemical Problems 19, no. 1 (2021): 25–31. http://dx.doi.org/10.32737/2221-8688-2021-1-25-31.

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The work deals with the reaction of ethanol conversion over chromium copper binary oxide catalysts. It showed that acetaldehyde is the main product of the ethanol conversion reaction. As the temperature rises, the direction of the ethanol conversion reaction shifts toward dehydration of ethanol into ethylene. Studies revealed that the atomic ratio of chromium to copper in the composition of the catalyst also has a strong effect on the activity of chromium-copper oxide catalysts. It established that samples with high chromium content in the composition of the catalyst display the greatest activity in the reaction of acetic aldehyde formation. So, on the sample Cr-Cu = 6-4, the yield of acetaldehyde reaches 82.5% with a selectivity of 97.6%. X-ray studies found that Cr-Cu-O catalysts consist mainly of initial oxides and in some samples indicate the chemical compound. X-ray studies showed that as the copper content decreases, the degree of crystallinity increases in the studied catalytic system. Comparison of the activity of Cr-Cu-O catalysts with their crystallinity degree revealed that the rise in crystallinity degree of chromium-copper oxide catalysts leads to the increase of acetic aldehyde yield and its selectivity in the ethanol conversion reaction.

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31

Pillis, M. F., Edval G. de Araújo, and Lalgudi Venkataraman Ramanathan. "Effect of Addition of Rare Earth Oxide Concentrates on Oxidation Resistance of AISI 304L." Materials Science Forum 530-531 (November 2006): 99–104. http://dx.doi.org/10.4028/www.scientific.net/msf.530-531.99.

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Rare earth elements are often added to chromium dioxide forming alloys to improve its high temperature oxidation resistance. The rare earths can be also added as oxide dispersions. Significant cost reductions are possible if rare earth oxide concentrates can be used instead of pure rare earth oxides, the former being the precursor to obtaining pure rare earth oxide. In this study the effect of adding pure and concentrates of rare earth oxides to AISI 304L on its oxidation behavior has been evaluated. AISI 304L stainless steel powder compacts containing 2 vol% of pure lanthanum and yttrium oxides or their concentrate were prepared by milling followed by pressing. The compacts were vacuum sintered and isothermally oxidized in air for up to 200h at 900°C. The parabolic rate constants were determined and the reaction products examined using a scanning electron microscope. X-ray diffraction analysis of the reaction products was also carried out. The compacts with pure rare earth oxides and the concentrates exhibited similar oxidation behavior.

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32

Fontana, S., M. Vuksa, Sébastien Chevalier, G. Caboche, and P. Piccardo. "On the Effect of Surface Treatment to Improve Oxidation Resistance and Conductivity of Metallic Interconnects for SOFC in Operating Conditions." Materials Science Forum 595-598 (September 2008): 753–62. http://dx.doi.org/10.4028/www.scientific.net/msf.595-598.753.

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Due to the reduction of operating temperature from 1000°C to 800°C, chromia forming alloys are the best candidates for interconnects in Solid Oxide Fuel Cells (SOFCs). These interconnects have to be operational in service conditions, at 800°C in air (cathode side) and in humidified hydrogen (anode side). The performance of the interconnect stainless steels is limited by the oxide scale formation (chromia), the low electronic conductivity of this scale and the possible volatility of chromium oxides. In the field of high temperature oxidation of metals, it is well known that the addition of a nanometric layer made of reactive element oxide such as, La2O3, Nd2O3 and Y2O3 by MOCVD (Metal Organic Chemical Vapor Deposition) on alloy surface resulted in an important improvement in the high temperature oxidation resistance. These coatings are made on metallic alloys in order to form perovskite oxides such as LaCrO3, NdCrO3 and YCrO3, which are expected to present a good conductivity at 800°C in air. However, this temperature looks somewhat too low to guarantee the formation of perovskite oxides and thus to improve the oxidation resistance and electrical conductivity. In fact, XRD analyses revealed that for Y2O3 coatings, perovskite oxides were not formed after oxidation in air at 800°C for 100 hours. The goal of this study is to perform pre-oxidation at 1000°C for 2 hours in air under atmospheric pressure on coated Crofer22APU to pre-form perovskite phases. The so-prepared perovskite were tested in a thermobalance in air. Experiments performed in H2/10%H2O under 150 mbar at 800°C validated the coating influence from the anode side as well as the cathode side. The corrosion products were analyzed after 100 hours ageing at 800°C by SEM, EDX, and XRD. ASR (Area Specific Resistance) was measured for the same times and temperature in air.

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33

O'Brien, Anthony B., Michael G. Segal, and William J. Williams. "Kinetics of metal oxide dissolution. Oxidative dissolution of chromium from mixed nickel–iron–chromium oxides by permanganate." Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases 83, no. 2 (1987): 371. http://dx.doi.org/10.1039/f19878300371.

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34

Gryshyn, Oleksandr, Angela Nadtochij, Nataliia Velykonska, and Yevhenii Zykin. "THERMODYNAMIC LAWS OF CHROMIUM REDUCTION BY MIXTURES OF СН4 + Н2О AND СН4 + СО2." Modern Problems of Metalurgy, no. 23 (March 27, 2020): 20–29. http://dx.doi.org/10.34185/1991-7848.2020.01.03.

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The development of a physico-chemical model of methane behavior in the processes of solid-phase reduction of chromium-containing raw materials will allow us to create the technological basis for the production of multicomponent sponge ligatures. The reduction of oxides with methane is accompanied by the deposition of soot carbon. The negative effect of carbon black, which is blocking the reaction surface, can be eliminated by adding carbon dioxide or water vapor to methane. A thermodynamic analysis of the reduction of chromium oxide with mixtures of CH4-CO2, CH4-H2O was carried out. The effect of the partial replacement of methane by carbon on the thermodynamic preferences of the process is analyzed. A physicochemical model of the behavior of the CH4 molecule in the recovery process is proposed. The thermodynamic features of reduction at various ratios of СН4 are considered: (Н2О, СО2, О2), as well as the composition of the mixture (Н2О+СО2+О2), which ensure the conditions of solid-phase reduction of oxides and the product of carbide destruction. The use of CH4 + H2O + O2 mixtures in the reduction of chromium oxide is thermodynamically less effective. The use of a mixture of СН4 + Н2О + СО2 has a very insignificant effect on the conversion of methane, and also reduces the thermodynamic preference for the reduction of Cr2O3 in comparison with СН4 + Н2О + О2 and СН4 + Н2О. However, it should be noted that in addition to CO and H2, carbon can be present in the reduction products, so the high reduction potential in this process variant (C+CO+H2) can be used to reduce oxides. The reduction of chromium oxide with mixtures of СН4 + Н2О + О2, СН4 + Н2О, and СН4 + Н2О + СО2 can be thermodynamically realized in the temperature range excluding the melting of the charge. As a result of this process, a carbide phase is formed, as well as a gas phase, which has a high reduction potential and can be used in further technological schemes. Meanwhile, it seems possible to control the carbon content in the sponge ligature by selecting the optimal composition of the source gas mixture.

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35

Rocha, Janaína de Lima, Rafael dos Santos Pereira, Mara Cristina Lopes de Oliveira, and Renato Altobelli Antunes. "Investigation on the Relationship between the Surface Chemistry and the Corrosion Resistance of Electrochemically Nitrided AISI 304 Stainless Steel." International Journal of Corrosion 2019 (February 3, 2019): 1–12. http://dx.doi.org/10.1155/2019/7023283.

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The relationship between the surface chemistry and the corrosion resistance of electrochemically nitrided AISI 304 stainless steel samples has been investigated. The nitriding treatment was carried out in HNO3 0.1 M and HNO3 0.1 M + KNO3 0.5 M at room temperature. Samples were subjected to the nitriding procedure for 30 minutes under a cathodic potential of -0.7 VAg/AgCl. The chemical composition of the nitrided layers was assessed by X-ray photoelectron spectroscopy (XPS). Depth profiles of the main elements present in the nitrided layers were also obtained by XPS by etching them with argon ions. The corrosion behavior of the nitrided samples was evaluated by potentiodynamic polarization. The results showed that the nitrided layers consisted of a mixture of chromium nitrides, chromium oxides, iron oxides/oxyhydroxides, and nickel oxide. The best corrosion resistance was obtained by electrochemical nitriding in the HNO3 0.1 M + KNO3 0.5 M solution. This result could be correlated with the composition and thickness of the nitrided layer.

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36

Rosales, I., D. Ponce, MJ Garcia-Ramirez, and R. Guardian. "Effect of Chromium Addition on the Cyclic Oxidation Resistance of Pseudo-Binary (Mo,Cr)3 Si Silicide Alloy." High Temperature Materials and Processes 37, no. 9-10 (October 25, 2018): 943–49. http://dx.doi.org/10.1515/htmp-2017-0099.

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AbstractThis paper describes the performance under cyclic oxidation of (Mo,Cr)3 Si compound with different Cr additions for possible coating application. Cyclic oxidation was carried out at 1,000 °C at different intervals during 250 h. Oxidized surface samples were analysed by scanning electron microscope where epitaxial oxide scales were observed mainly in samples with higher Cr content which may provide protection against surface oxidation. X-ray diffraction studies have shown the Cr2O3 and SiO2 formation as the main oxide scale; after analyses, it was found that these oxides are responsible for the best oxidation protection, with 36 at.% Cr being the optimal chromium concentration. At lower chromium concentrations, pest reaction occurred in the oxidized samples at times less than 25 h as a result of the formation of the unstable molybdenum oxide.

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37

Catalá, R., M. Alonso, R. Gavara, E. Almeida, J. M. Bastidas, J. M. Puente, and N. de Cristaforo. "Titanium-Passivated Tinplate for Canning Foods." Food Science and Technology International 11, no. 3 (June 2005): 223–27. http://dx.doi.org/10.1177/1082013205054933.

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Chromium-based treatments are currently used for the passivation of tinplate, which produces a protective surface layer consisting of a mixture of metal chromium and chromium oxide. This passivation film is effective against the formation of tin oxides and corrosion by food media, and offers a good substrate for the adhesion of protective organic coatings. However, there is an increasing concern about environmental and health risks with this passivation treatment. The aim of this paper was to study a new environmental friendly passivation treatment based on a titanium compound, applied on tinplate and afterwards lacquered with a conventional epoxyphenolic lacquer used for food can applications. The mechanical and electrochemical characteristics of the lacquered material and the metallic dissolution in canned sardines in tomato juice and peeled tomato were similar to those obtained with conventional Cr-passivated tinplate. According to these results titanium treatment could be considered an alternative to chromium for practical applications.

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38

Vokov, V. L., G. S. Zakharova, L. V. Strukova, T. Edkhazi, and O. V. Pozdnyakova. "Reduction of nitrogen oxides with ammonia over complex vanadium and chromium oxides." Russian Chemical Bulletin 45, no. 2 (February 1996): 324–27. http://dx.doi.org/10.1007/bf01433965.

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39

Ursu, Luminita Daniela, Adriana Diaconu, Bogdan Alexandru Sava, Lucica Boroica, Ileana Mitiu, Elisabeta Rosu, Dorel Radu, M. Dinulescu, and Mihai Eftimie. "A Study of the Industrial Waste Incorporating in Glass." Advanced Materials Research 39-40 (April 2008): 675–78. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.675.

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The paper presents a study of the industrial waste incorporating in glass in order to obtain decorative colored glasses. The influence of iron and chromium oxides from waste amount is discussed. The samples properties such as density, thermal expansion coefficient and viscosity are investigated. Including different oxides of heavy metals (obtained from sludge that contains chromium and iron) into the vitreous system leads to the obtaining of several decorative glasses. Their colour varies widely, to the added quantity and the atmosphere of the work place.

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40

Xiao, Yanping, and Lauri Holappa. "Determination of Activities in Slags Containing Chromium Oxides." ISIJ International 33, no. 1 (1993): 66–74. http://dx.doi.org/10.2355/isijinternational.33.66.

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41

Koksbang, R., S. Yde-Andersen, K. West, B. Zachau-Christiansen, and S. Skaarup. "Lithium and sodium insertion in ternary chromium oxides." Solid State Ionics 28-30 (September 1988): 868–72. http://dx.doi.org/10.1016/s0167-2738(88)80161-9.

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42

Gu, LiNa, and GuangYao Meng. "Synthesis and characterization of two PbO-chromium oxides." Powder Technology 178, no. 1 (September 2007): 1–4. http://dx.doi.org/10.1016/j.powtec.2007.01.017.

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43

Suzuki, Ryosuke O., Takamichi Ogawa, and Ryosuke Kondo. "Synthesis of Higher Chromium Oxides Using Ozone Gas." Journal of the American Ceramic Society 91, no. 4 (April 2008): 1148–54. http://dx.doi.org/10.1111/j.1551-2916.2005.00862.x.

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44

Ezhovskii, Yu K. "Surface modification of silicate matrices with chromium oxides." Russian Journal of Physical Chemistry A 89, no. 8 (July 8, 2015): 1471–75. http://dx.doi.org/10.1134/s0036024415080117.

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45

Mittal, Ayush, Galina Jelkina Albertsson, Govind Sharan Gupta, Seshadri Seetharaman, and Sankaran Subramanian. "Some Thermodynamic Aspects of the Oxides of Chromium." Metallurgical and Materials Transactions B 45, no. 2 (February 20, 2014): 338–44. http://dx.doi.org/10.1007/s11663-014-0027-x.

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46

Zhang, Yan-ling, Wen-ming Guo, and Xin-lei Jia. "Reduction of chromium oxides in stainless steel dust." International Journal of Minerals, Metallurgy, and Materials 22, no. 6 (June 2015): 573–81. http://dx.doi.org/10.1007/s12613-015-1109-8.

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47

Allen, G. C., J. A. Jutson, and P. A. Tempest. "Characterisation of manganese-chromium-iron spinel-type oxides." Journal of Nuclear Materials 160, no. 1 (November 1988): 34–47. http://dx.doi.org/10.1016/0022-3115(88)90005-0.

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48

Allen, Geoffrey C., Josephine A. Jutson, and Paul A. Tempest. "Characterization of nickel-chromium-iron spinel-type oxides." Journal of Nuclear Materials 158 (August 1988): 96–107. http://dx.doi.org/10.1016/0022-3115(88)90159-6.

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49

Armor, J. N., E. J. Carlson, and W. C. Conner. "Synthesis of high surface area chromium(III) oxides." Reactivity of Solids 3, no. 1-2 (April 1987): 155–59. http://dx.doi.org/10.1016/0168-7336(87)80025-6.

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50

Chang, Chun Liang, Chang Sing Hwang, Chun Huang Tsai, Sheng Fu Yang, Wei Ja Shong, Te Jung Daron Huang, and Zong Yang Jhuang-Shie. "Preparation and Characterization of Protective LSM Coatings Produced by Atmospheric Plasma Spraying." Key Engineering Materials 656-657 (July 2015): 68–73. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.68.

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Lanthanum strontium manganite oxides with perovskite structure are widely employed materials for protective coatings on chromium-contained metallic interconnectors in the intermediated temperature solid oxide fuel cells (ITSOFCs). The application of protective coatings is used to decrease the growth of chromium oxide and the evaporation of chromium trioxide and chromium hydroxide from the surfaces of metallic interconnectors. In this study, La0.8Sr0.2MnO3-δ(LSM) protective coatings are produced by the promising atmospheric plasma spraying (APS) technique on the substrates of Crofer 22 H, Crofer 22 APU and SS441 ferritic steels with or without pre-oxidation treatment. The substrates with pre-oxidation treatment were heated to 800°C and dwelled for 12 hrs in air before APS coating process. The cross-sectional micrographs show that the LSM coatings produced by APS technique are quiet dense without penetrating cracks. The XRD results identify that the LSM coatings produced by APS under 50 kW torch power reveal desired perovskite structure without any X-ray detectable second phase. After 600 hrs ageing in air at 800°C, the initial and final ASR values of the coated Crofer 22 APU sample with pre-oxidation treatment are 1.350 and 1.694 mΩcm2, respectively. The measured ASR increasing rate is only about 0.573 μΩcm2/hr. Thus, LSM coating prepared by APS technique can dramatically decrease the growth of chromium oxide to protect the metallic interconnector and the generation of gaseous Cr-contained species to avoid cathode poisoning at the operating temperatures of ITSOFCs.

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