The role of boric acid in the copper tin alloy bath has been investigated by means of the cathodic polarization curves,cyclic voltammograms,rate of alloy electrodeposition and morphological analysis of deposits.The r...The role of boric acid in the copper tin alloy bath has been investigated by means of the cathodic polarization curves,cyclic voltammograms,rate of alloy electrodeposition and morphological analysis of deposits.The results indicate that the presence of boric acid in weak acidic solution for electrodeposition of Cu Sn alloy raises the overvoltage of hydrogen discharge and lowers the overvoltage of Cu,Sn and Cu Sn alloy deposition on the Pt,and accelerates the rate of depostion.Boric acid was adsorbed on the surface of cathode and inhibited reduction of hydrogen,then the adsorbed boric acid promoted electrodeposition of metals as a catalyzator.However,as the concentration of boric acid is more than 0.50 mol/L,the above effect was weakened due to the complexation reaction between the excessive boric acid and metallic ions.展开更多
Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from th...Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.展开更多
The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to l...The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and SnoTi subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattice theory （QLT）. This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.展开更多
文摘The role of boric acid in the copper tin alloy bath has been investigated by means of the cathodic polarization curves,cyclic voltammograms,rate of alloy electrodeposition and morphological analysis of deposits.The results indicate that the presence of boric acid in weak acidic solution for electrodeposition of Cu Sn alloy raises the overvoltage of hydrogen discharge and lowers the overvoltage of Cu,Sn and Cu Sn alloy deposition on the Pt,and accelerates the rate of depostion.Boric acid was adsorbed on the surface of cathode and inhibited reduction of hydrogen,then the adsorbed boric acid promoted electrodeposition of metals as a catalyzator.However,as the concentration of boric acid is more than 0.50 mol/L,the above effect was weakened due to the complexation reaction between the excessive boric acid and metallic ions.
文摘Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.
基金This work was financially supported by THERMOLAB - ESA MAP PROJECT, Contract No. AO-99-022. A part of this work was performed in the framework of the E.C. action COST 531 project: "Lead-free solder materials".
文摘The lack of experimental data and / or limited experimental information concerning both surface and transport properties of liquid alloys often require the prediction of these quantities. An attempt has been made to link the thermophysical properties of a ternary Cu-Sn-Ti system and its binary Cu-Sn, Cu-Ti and SnoTi subsystems with the bulk through the study of the concentration dependence of various thermodynamic, structural, surface and dynamic properties in the frame of the statistical mechanical theory in conjunction with the quasi-lattice theory （QLT）. This formalism provides valuable qualitative insight into mixing processes that occur in molten alloys.
