Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions....Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn（OH）4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag＋ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction （XRD） analysis,scanning electron microscope （SEM）,and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.展开更多
A Ti^4＋-doped nano-structured AgSnO2 material was prepared using sol-gel method and characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and scanning electron microscopy （SEM）. The ...A Ti^4＋-doped nano-structured AgSnO2 material was prepared using sol-gel method and characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and scanning electron microscopy （SEM）. The results show that Ti^4＋ cations are successfully doped into the crystal lattice of SnO2, and thus significantly improve the electrical conductivity of the sample. Furthermore, the coating of Ag on Ti^4＋-doped SnO2 nano-sized particles enhances the surface wettability and enables the resulting AgSnO2 material to have better mechanical properties.展开更多
Constituents of the oxidized surface film on diamond particles reinforced Cu-Cd alloy matrix composite （Cp/Cu-Cd） were investigated by XPS. The results show that Cu2O is the main constituent when the oxidized film i...Constituents of the oxidized surface film on diamond particles reinforced Cu-Cd alloy matrix composite （Cp/Cu-Cd） were investigated by XPS. The results show that Cu2O is the main constituent when the oxidized film is thin; CuO appears only after the film is rather thick. The originally formed oxidized film on the Cp/Cu-Cd is about 10nm in thickness and is mainly composed of Cu2O and Cu. After oxidized at 120℃ over 30h, CuO is detected in the film.展开更多
A super-fine compound powder, Ag/SnO_2+La_2O_3+ Bi_2O_3, has been obtainedusing the chemical coprecipitation method. And a new contact material, Ag/SnO_2+La_2O_3+Bi_2O_3, wasproduced by the powder metallurgy method. I...A super-fine compound powder, Ag/SnO_2+La_2O_3+ Bi_2O_3, has been obtainedusing the chemical coprecipitation method. And a new contact material, Ag/SnO_2+La_2O_3+Bi_2O_3, wasproduced by the powder metallurgy method. Its properties are as follows: the density is 9.75-9.93g/cm^3, the resistivity is 2.31-2.55 μΩ ·cm, the hardness is 880-985 MPa. Its mi-crostructureshows that the fine oxides have a uniform distribution in the silver matrix. The results ofmake-break capacity and temperature rise testing show that the new material has better ability ofanti-arc erosion and lower temperature rise than that of commonly used Ag/CdO.展开更多
A new silver rare earth oxide contact material, Ag/La2O3(12), was produced by powder metallurgy method. Its performances are as follows: the density is 9.71 similar to 9.96 g.cm(-3); the hardness (HB) is 760 similar t...A new silver rare earth oxide contact material, Ag/La2O3(12), was produced by powder metallurgy method. Its performances are as follows: the density is 9.71 similar to 9.96 g.cm(-3); the hardness (HB) is 760 similar to 970 MPa and the resistivity is 2.25 similar to 2.38 mu Omega . cm. The microstructure of Ag/La2O3(12) mas analyzed by SEM and EDS. Rare earth oxide La2O3 shows two shapes, which are uniformly distributed in the form of sphere and abnormality in Ag matrix. La2O3 shows fine spherical shape in the melted area of Ag after laser acting which is used to simulate electric are. The results are contributed to the less splash erosion of Ag. Compared with the main physical and mechanical properties of Ag/SnO2(12) and Ag/CdO(12), the properties of three contact materials are similar, and hence Ag/La2O3(12) may become a potential contact material to be used as the substitute of Ag/CdO(12).展开更多
Silver in the form of AgNO3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method.The effects of AgNO3 on both the microstructure and electrical properties of the varistors were studied ...Silver in the form of AgNO3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method.The effects of AgNO3 on both the microstructure and electrical properties of the varistors were studied in detail.The optimum addition amount of AgNO3 in ZnO-based varistors was also determined.The mechanism for grain growth inhibition by silver doping was also proposed.The results indicate that the varistor threshold voltage increases substantially along with the AgNO3 content increasing from 0 to 1.5mol%.Also,the introduction of AgNO3 can depress the mean grain size of ZnO,which is mainly responsible for the threshold voltage.Furthermore,the addition of AgNO3 results in a slight decrease of donor density and a more severe fall in the density of interface states,which cause a decline in barrier height and an increase in the depletion layer.展开更多
文摘Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn（OH）4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag＋ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction （XRD） analysis,scanning electron microscope （SEM）,and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.
文摘A Ti^4＋-doped nano-structured AgSnO2 material was prepared using sol-gel method and characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and scanning electron microscopy （SEM）. The results show that Ti^4＋ cations are successfully doped into the crystal lattice of SnO2, and thus significantly improve the electrical conductivity of the sample. Furthermore, the coating of Ag on Ti^4＋-doped SnO2 nano-sized particles enhances the surface wettability and enables the resulting AgSnO2 material to have better mechanical properties.
文摘Constituents of the oxidized surface film on diamond particles reinforced Cu-Cd alloy matrix composite （Cp/Cu-Cd） were investigated by XPS. The results show that Cu2O is the main constituent when the oxidized film is thin; CuO appears only after the film is rather thick. The originally formed oxidized film on the Cp/Cu-Cd is about 10nm in thickness and is mainly composed of Cu2O and Cu. After oxidized at 120℃ over 30h, CuO is detected in the film.
基金This project is financially supported by the Science Foundation of Hebei Province (No.502048)
文摘A super-fine compound powder, Ag/SnO_2+La_2O_3+ Bi_2O_3, has been obtainedusing the chemical coprecipitation method. And a new contact material, Ag/SnO_2+La_2O_3+Bi_2O_3, wasproduced by the powder metallurgy method. Its properties are as follows: the density is 9.75-9.93g/cm^3, the resistivity is 2.31-2.55 μΩ ·cm, the hardness is 880-985 MPa. Its mi-crostructureshows that the fine oxides have a uniform distribution in the silver matrix. The results ofmake-break capacity and temperature rise testing show that the new material has better ability ofanti-arc erosion and lower temperature rise than that of commonly used Ag/CdO.
文摘A new silver rare earth oxide contact material, Ag/La2O3(12), was produced by powder metallurgy method. Its performances are as follows: the density is 9.71 similar to 9.96 g.cm(-3); the hardness (HB) is 760 similar to 970 MPa and the resistivity is 2.25 similar to 2.38 mu Omega . cm. The microstructure of Ag/La2O3(12) mas analyzed by SEM and EDS. Rare earth oxide La2O3 shows two shapes, which are uniformly distributed in the form of sphere and abnormality in Ag matrix. La2O3 shows fine spherical shape in the melted area of Ag after laser acting which is used to simulate electric are. The results are contributed to the less splash erosion of Ag. Compared with the main physical and mechanical properties of Ag/SnO2(12) and Ag/CdO(12), the properties of three contact materials are similar, and hence Ag/La2O3(12) may become a potential contact material to be used as the substitute of Ag/CdO(12).
基金supported by the National Natural Science Foundation of China (Nos.50571059 and 50615024)the Natural Science Foundation of Jiangsu Province,China (No.SBK200920379)the Program for New Century Excellent Talents in Chinese Universities (No.NCET-07-0536)
文摘Silver in the form of AgNO3 was added to ZnO-based varistor ceramics prepared by the solid-state reaction method.The effects of AgNO3 on both the microstructure and electrical properties of the varistors were studied in detail.The optimum addition amount of AgNO3 in ZnO-based varistors was also determined.The mechanism for grain growth inhibition by silver doping was also proposed.The results indicate that the varistor threshold voltage increases substantially along with the AgNO3 content increasing from 0 to 1.5mol%.Also,the introduction of AgNO3 can depress the mean grain size of ZnO,which is mainly responsible for the threshold voltage.Furthermore,the addition of AgNO3 results in a slight decrease of donor density and a more severe fall in the density of interface states,which cause a decline in barrier height and an increase in the depletion layer.
