Arc erosion behavior of Ag/Ni materials with different operation numbers was investigated by OM,3DOP and SEM.The results indicated that the arc erosion of Ag/10Ni electrical contact material fabricated by sintering−ex...Arc erosion behavior of Ag/Ni materials with different operation numbers was investigated by OM,3DOP and SEM.The results indicated that the arc erosion of Ag/10Ni electrical contact material fabricated by sintering−extrusion technology was more and more serious with the operation numbers increasing from 1000 to 40000.With the same operation numbers,the arc erosion on anode was more serious than that on cathode.Besides,the pores preferred to emerge around the arc effect spot during the first 10000 operations.And the morphology of the molten silver on cathode and anode was different due to the action of gravity and arc erosion.Furthermore,the relationships among arc energy,arc time,welding force,electric resistivity,temperature and mass change on contacts were discussed,which indicated that the mass loss on cathode was mainly caused by the fracture of molten bridge.展开更多
The technology of cold pressure welding was adopted to achieve the bonding of Al/Cu(limited soluble and forming compounds), Ag/Ni (hardly mutual soluble), and the relative state of interface was tested by HREM. The re...The technology of cold pressure welding was adopted to achieve the bonding of Al/Cu(limited soluble and forming compounds), Ag/Ni (hardly mutual soluble), and the relative state of interface was tested by HREM. The results indicate that stable interface is always corresponding to the low interfacial energy value; the stable interface is not coherent but partly-coherent because of the twisting of grain boundary caused by pressure, meanwhile existing dislocation. Namely, the interfacial match and other states under the condition of cold pressure welding are different from the situation that under the condition of thermal action. Moreover, theoretical analyses and calculation on the base of thermodynamics, crystallogeny, solid physics etc, were discussed.展开更多
To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223...To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223/Ag/Ni tapes were studied. The phase compositions of the samples were characterized using XRD. The microstructure was observed using SEM. Experimental results indicate that higher temperature is more conducive to the formation of Bi-2223 phase at an atmosphere of 8.5% O 2 . After the two-step heat treatment, the critical current of samples is about 67.5 A.展开更多
基金supported by the National Natural Science Foundation of China (No.51601225)Hunan Provincial Natural Science Foundation,China (No.2020JJ5742)。
文摘Arc erosion behavior of Ag/Ni materials with different operation numbers was investigated by OM,3DOP and SEM.The results indicated that the arc erosion of Ag/10Ni electrical contact material fabricated by sintering−extrusion technology was more and more serious with the operation numbers increasing from 1000 to 40000.With the same operation numbers,the arc erosion on anode was more serious than that on cathode.Besides,the pores preferred to emerge around the arc effect spot during the first 10000 operations.And the morphology of the molten silver on cathode and anode was different due to the action of gravity and arc erosion.Furthermore,the relationships among arc energy,arc time,welding force,electric resistivity,temperature and mass change on contacts were discussed,which indicated that the mass loss on cathode was mainly caused by the fracture of molten bridge.
文摘The technology of cold pressure welding was adopted to achieve the bonding of Al/Cu(limited soluble and forming compounds), Ag/Ni (hardly mutual soluble), and the relative state of interface was tested by HREM. The results indicate that stable interface is always corresponding to the low interfacial energy value; the stable interface is not coherent but partly-coherent because of the twisting of grain boundary caused by pressure, meanwhile existing dislocation. Namely, the interfacial match and other states under the condition of cold pressure welding are different from the situation that under the condition of thermal action. Moreover, theoretical analyses and calculation on the base of thermodynamics, crystallogeny, solid physics etc, were discussed.
基金financially supported by the National High Technology Research and Development Program(863program)(No.2009AA03Z202)the Fundamental Research Funds for the Central Universities(No.N100423006and No.N110823001)
文摘To reduce the production cost of Bi-2223 superconducting tapes, Bi-2223/Ag/Ni tapes were fabricated by the powder-in-tube process. The effect of heat treatment on the microstructure and critical current of the Bi-2223/Ag/Ni tapes were studied. The phase compositions of the samples were characterized using XRD. The microstructure was observed using SEM. Experimental results indicate that higher temperature is more conducive to the formation of Bi-2223 phase at an atmosphere of 8.5% O 2 . After the two-step heat treatment, the critical current of samples is about 67.5 A.
基金National High Technology Research and Development Program(863 program)(2009AA03Z202)Fundamental Research Funds for the Central Universities(N100423006,N110823001,N100123003)
