Results 221 to 230 of about 18,068 (261)
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The Journal of Chemical Physics, 1969
The thermoluminescence of ZrO2 samples, both pure and doped with titanium, irradiated with low doses of x rays has been studied. The glow curve of ZrO2(Ti) exhibits, in the temperature range 100° to 350°K, four main peaks all having the same spectral composition.
C. Bettinali +2 more
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The thermoluminescence of ZrO2 samples, both pure and doped with titanium, irradiated with low doses of x rays has been studied. The glow curve of ZrO2(Ti) exhibits, in the temperature range 100° to 350°K, four main peaks all having the same spectral composition.
C. Bettinali +2 more
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Stabilization of the cubic ZrO2 phase in the system ZrO2-MgO
Thermochimica Acta, 1990Abstract By progressive calcination of coprecipitated gels with a molar Zr-Mg ratio of 1:1, at different digestion times, it is found that, at temperatures of −700 °C, a cubic solid solution plus MgO is formed. This solid solution is transformed to a tetragonal structure at ~ 950 °C.
M.J. Martinez-Lope +2 more
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Effect of hydrogen treatments on ZrO2 and Pt/ZrO2 catalysts
Catalysis Letters, 1994ZrO2 and Pt/ZrO2 catalysts have been investigated by TPR, hydrogen chemisorption, TPDH and in the conversion ofn-hexane. At high temperature, ZrO2 takes up hydrogen. High temperature hydrogen treatment is a precondition of the catalytic activity in then-hexane conversion.
D. L. Hoang, H. Lieske
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2011
Mesoporous zirconia aerogels are very interesting materials with important properties used for several applications such as ceramics and catalysis. The textural and structural properties of zirconia aerogel depend on the preparation parameters such as the hydrolysis ratio, the acid and zirconium precursor concentrations, and the gel aging.
Lassaad Ben Hammouda +3 more
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Mesoporous zirconia aerogels are very interesting materials with important properties used for several applications such as ceramics and catalysis. The textural and structural properties of zirconia aerogel depend on the preparation parameters such as the hydrolysis ratio, the acid and zirconium precursor concentrations, and the gel aging.
Lassaad Ben Hammouda +3 more
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Applied Catalysis B: Environmental, 2002
Copper oxide supported on ZrO2 catalysts (CuOx/ZrO2) were prepared by impregnation of ZrO2 with aqueous solutions of Cu(NO3)2. Copper sulphated- zirconia catalysts were prepared by three different methods: (i) impregnation of ZrO2 with aqueous solutions of CuSO4, (ii) impregnation of sulphated-ZrO2 with toluene solutions of Cu(acetylacetonate)2, and ...
INDOVINA, Valerio +2 more
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Copper oxide supported on ZrO2 catalysts (CuOx/ZrO2) were prepared by impregnation of ZrO2 with aqueous solutions of Cu(NO3)2. Copper sulphated- zirconia catalysts were prepared by three different methods: (i) impregnation of ZrO2 with aqueous solutions of CuSO4, (ii) impregnation of sulphated-ZrO2 with toluene solutions of Cu(acetylacetonate)2, and ...
INDOVINA, Valerio +2 more
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Sliding wear of Cr–Al2O3–ZrO2 and Mo–Al2O3–ZrO2 composites
Journal of the European Ceramic Society, 2005The sliding wear behavior of a number of reactively sintered metal-alumina- composites (s-MAC) containing zirconia and pure alumina and yttria-stabilized zirconia (3Y-TZP) reference materials were investigated using a ball-on-disk method. Samples were tested against stainless steel (s/steel) and 3Y-TZP ball-sliders.
S Scheppokat +4 more
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Structural and Optical Characterization of ZrO2 and Y2O3-ZrO2 Nanopowders
2015Structural and optical properties of pure and Y-doped ZrO2 nanopowders with different Y content sintered by co-precipitation of Zr and Y nitrates were investigated. It was observed that the increase of Y content stimulates the transformation of crystalline phase from monoclinic through tetragonal to cubic while the increase of calcinations time leads ...
Nadiia Korsunska +10 more
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Glass Physics and Chemistry, 2006
Structural and chemical transformations in the ZrO2-Al2O3 and ZrO2-SiO2 systems containing ZrO2 nanocrystals are examined. It is shown that the presence of zirconia nanoparticles in the oxide mixture retards the processes of crystallization and phase formation.
O. V. Almjasheva, V. V. Gusarov
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Structural and chemical transformations in the ZrO2-Al2O3 and ZrO2-SiO2 systems containing ZrO2 nanocrystals are examined. It is shown that the presence of zirconia nanoparticles in the oxide mixture retards the processes of crystallization and phase formation.
O. V. Almjasheva, V. V. Gusarov
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Catalysis Today, 1998
Abstract In the paper, we review the preparation and the characterization of CrOx/ZrO2, MoOx/ZrO2 and VOx/ZrO2. Catalysts were prepared by various methods (equilibrium adsorption, impregnation or mechanical mixing) and characterized by XRD, XPS, ESR and FTIR techniques. In the paper, we also review the catalytic activity of the ZrO2 supported systems
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Abstract In the paper, we review the preparation and the characterization of CrOx/ZrO2, MoOx/ZrO2 and VOx/ZrO2. Catalysts were prepared by various methods (equilibrium adsorption, impregnation or mechanical mixing) and characterized by XRD, XPS, ESR and FTIR techniques. In the paper, we also review the catalytic activity of the ZrO2 supported systems
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2013
Variation of fracture toughness KIc of ZrO2- Y2O3 ceramics (density ~ 98%) was studied depending on both testing machine traverse speed (0.005-50 mm/min) and preloading under KI < KIc conditions. It was demonstrated that within a strain-rate range from 0.05 to 5 mm/min fracture toughness practically does not change.
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Variation of fracture toughness KIc of ZrO2- Y2O3 ceramics (density ~ 98%) was studied depending on both testing machine traverse speed (0.005-50 mm/min) and preloading under KI < KIc conditions. It was demonstrated that within a strain-rate range from 0.05 to 5 mm/min fracture toughness practically does not change.
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