Thermodynamic assessment in the ternary systems ZrO2 -CeO2 -Y2 O3, ZrO2 -CeO2 -Ce2 03 and the limiting binaries ZrO2 -Y2 O3, ZrO2 -CeO2, CeO2 -Y2 03, ZrO2 -Ce2O3, CeO2 -Ce2O3 as well as the modeling for oxides are rev...Thermodynamic assessment in the ternary systems ZrO2 -CeO2 -Y2 O3, ZrO2 -CeO2 -Ce2 03 and the limiting binaries ZrO2 -Y2 O3, ZrO2 -CeO2, CeO2 -Y2 03, ZrO2 -Ce2O3, CeO2 -Ce2O3 as well as the modeling for oxides are reviewed comprehensively. Based on the recent estimations on the YO1.5-CeO2, ZrO2-CeO2 and ZrO2 -YO1.6 systems, isothermal sections at 1273 and 1 973 K of the ternary CeO2- ZrO2-YO1.5system are calculated. In the system of ZrO2-CeO2-Ce2O3, the complex relation between the nonstoichiometry （y） in CeO2-x, the composition of the ZrO2 -CeO2 solid solution and the oxygen partial pressure （Po2 ） for different ZrO2 containing solid solutions CexZr1-xO2-x. are evaluated from 1 473 to 1 773 K. The relation between the degree of Ce^＋4 reduction to Ce.3 under different Po2 in the fluorite CeO2-xy and CexZr1-xOz-x solid solutions at different temperatures can be used as a guide in the development of functional ceramics.展开更多
The ZrO2 thin films deposited on Si (100) were successfully synthesized by solgel process and deposited by using spin-coating technique.The structural properties of ZrO2 thin films were investigated by X-Ray Diffracti...The ZrO2 thin films deposited on Si (100) were successfully synthesized by solgel process and deposited by using spin-coating technique.The structural properties of ZrO2 thin films were investigated by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and electrical properties were studied by conventional techniques like Capacitance-Voltage (C-V) measurement and Current–Voltage (I–V) measurement. The XRD of ZrO2 films shows the films crystallized and exists in two phases at 700℃ calcinations temperature. The C–V characteristics of all the dielectric films that involved distinct inversion, depletion, and accumulation were clearly revealed in MIS structure. I-V characteristics of ZrO2 thin films on Si shows decreased saturation current on calcinations temperatures. The XPS measurement reveals that a zirconium silicate interfacial layer has formed in the ZrO2/Si Systems.展开更多
Surface metal matrix composite is produced on the as cast Magnesium Rare Earth alloy-RZ 5 by single pass friction stir processing using various micro/nano sized reinforcement particles namely Boron Carbide(B_(4)C),Mul...Surface metal matrix composite is produced on the as cast Magnesium Rare Earth alloy-RZ 5 by single pass friction stir processing using various micro/nano sized reinforcement particles namely Boron Carbide(B_(4)C),Multi Walled Carbon Nano Tubes(MWCNTs),and a mixture of ZrO_(2)+Al_(2)O_(3)particles.Fine grained metal matrix composites having the grain size ranging 0.8μm to 1.87μm are achieved.Grain boundary pinning by the reinforcement particles has resulted in the transformation of coarse grained(∼81μm)base material into fine grained(<1μm)metal matrix composite.Finer grain structure and the presence of reinforcements at the stir zone have resulted in increased and improved mechanical properties of the developed composites.Microhardness ranging between 125 HV and 403 HV is achieved.Uni-axial Tensile Testing of the developed composites exhibited improvement in tensile strength.Metal matrix composites developed using various reinforcements exhibited an increase in strength ranges between 250 MPa and 320 MPa.展开更多
Cu/ZrO2 catalysts for methanol synthesis from CO2/H2 were respectively prepared by deposition coprecipitation （DP） and solid state reaction （SR） methods. There is an intimate interaction between copper and zirconi...Cu/ZrO2 catalysts for methanol synthesis from CO2/H2 were respectively prepared by deposition coprecipitation （DP） and solid state reaction （SR） methods. There is an intimate interaction between copper and zirconia, which strongly affects the reduction property and catalytic performance of the catalysts. The stronger the interaction, the lower the reduction temperature and the better the performance of the catalysts. Surface area, pore structure and crystal structure of the catalysts are mainly controlled by preparation methods and alkalinity of synthesis system. The conversion of CO2 and selectivity of methanol are higher for DP catalysts than for SP catalysts.展开更多
文摘Thermodynamic assessment in the ternary systems ZrO2 -CeO2 -Y2 O3, ZrO2 -CeO2 -Ce2 03 and the limiting binaries ZrO2 -Y2 O3, ZrO2 -CeO2, CeO2 -Y2 03, ZrO2 -Ce2O3, CeO2 -Ce2O3 as well as the modeling for oxides are reviewed comprehensively. Based on the recent estimations on the YO1.5-CeO2, ZrO2-CeO2 and ZrO2 -YO1.6 systems, isothermal sections at 1273 and 1 973 K of the ternary CeO2- ZrO2-YO1.5system are calculated. In the system of ZrO2-CeO2-Ce2O3, the complex relation between the nonstoichiometry （y） in CeO2-x, the composition of the ZrO2 -CeO2 solid solution and the oxygen partial pressure （Po2 ） for different ZrO2 containing solid solutions CexZr1-xO2-x. are evaluated from 1 473 to 1 773 K. The relation between the degree of Ce^＋4 reduction to Ce.3 under different Po2 in the fluorite CeO2-xy and CexZr1-xOz-x solid solutions at different temperatures can be used as a guide in the development of functional ceramics.
文摘The ZrO2 thin films deposited on Si (100) were successfully synthesized by solgel process and deposited by using spin-coating technique.The structural properties of ZrO2 thin films were investigated by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and electrical properties were studied by conventional techniques like Capacitance-Voltage (C-V) measurement and Current–Voltage (I–V) measurement. The XRD of ZrO2 films shows the films crystallized and exists in two phases at 700℃ calcinations temperature. The C–V characteristics of all the dielectric films that involved distinct inversion, depletion, and accumulation were clearly revealed in MIS structure. I-V characteristics of ZrO2 thin films on Si shows decreased saturation current on calcinations temperatures. The XPS measurement reveals that a zirconium silicate interfacial layer has formed in the ZrO2/Si Systems.
文摘Surface metal matrix composite is produced on the as cast Magnesium Rare Earth alloy-RZ 5 by single pass friction stir processing using various micro/nano sized reinforcement particles namely Boron Carbide(B_(4)C),Multi Walled Carbon Nano Tubes(MWCNTs),and a mixture of ZrO_(2)+Al_(2)O_(3)particles.Fine grained metal matrix composites having the grain size ranging 0.8μm to 1.87μm are achieved.Grain boundary pinning by the reinforcement particles has resulted in the transformation of coarse grained(∼81μm)base material into fine grained(<1μm)metal matrix composite.Finer grain structure and the presence of reinforcements at the stir zone have resulted in increased and improved mechanical properties of the developed composites.Microhardness ranging between 125 HV and 403 HV is achieved.Uni-axial Tensile Testing of the developed composites exhibited improvement in tensile strength.Metal matrix composites developed using various reinforcements exhibited an increase in strength ranges between 250 MPa and 320 MPa.
文摘Cu/ZrO2 catalysts for methanol synthesis from CO2/H2 were respectively prepared by deposition coprecipitation （DP） and solid state reaction （SR） methods. There is an intimate interaction between copper and zirconia, which strongly affects the reduction property and catalytic performance of the catalysts. The stronger the interaction, the lower the reduction temperature and the better the performance of the catalysts. Surface area, pore structure and crystal structure of the catalysts are mainly controlled by preparation methods and alkalinity of synthesis system. The conversion of CO2 and selectivity of methanol are higher for DP catalysts than for SP catalysts.
