Effect of Cu Doping on the Properties of Ag/SnO2 Contact Materials
In order to systematically discuss the effect of Cu doping on the arc erosion resistance of Ag/SnO2 contact materials,Ag/SnO2 contact materials and Cu-doped Ag/SnO2 contact materials with different Cu additions were prepared.The phase composition,microstructure,and component distribution of SnO2 powder and Ag/SnO2 contact materials before and after arc erosion were characterized using XRD,TEM,SEM,and EDS,respectively.The physical properties and arc ersion resistance of Ag/SnO2 contact materials were tested,and the mechanism of Cu doping affecting the properties of Ag/SnO2 contact materials was ex-plored.The results indicate that doped Cu ions dissolve into the crystal structure of SnO2,resulting in lat-tice distortion,inhibiting the growth of SnO2 grains and reducing their grain size.With the increase of Cu addition,the hardness,resistivity and mass loss caused by arc erosion of Cu-doped Ag/SnO2 contact materi-als first decrease and then increase,while the density first increases and then decreases.The Cu-doped Ag/SnO2 contact material with a molar ratio of Cu to Sn of 0.12(Ag/0.12Cu-SnO2)has the lowest resistivi-ty,hardness and mass loss caused by arc erosion,and the highest density.Compared with the undoped Ag/SnO2 contact material,the microstructure uniformity of Ag/0.12Cu-SnO2 contact material is significantly improved,and its average resistivity,average hardness and mass loss caused by arc erosion of Ag/0.12Cu-SnO2 contact material are reduced by 13.33%,6.87%and 59.40%respectively,while the average density is increased by 4.11%.The arc erosion resistance of Ag/SnO2 electrical contact materials can be signifi-cantly improved by appropriate Cu addition,but excessive addition could reduce the resistance.The reason is that the grain size of Cu-doped SnO2 is reduced,which improves the interfacial bonding strength and wet-tability between SnO2 and the Ag matrix,inhibits SnO2 particles from escaping from the silver melt pool and enriching on the surface of the contact materials,and thus improves the arc erosion resistance of the Ag/SnO2 contact materials.
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