Effect of Cu, S Co-Doping on Properties of AgSnO2 Contact Material

The stability, elastic properties and conductive properties of Cu-doped SnO2, S-doped SnO2 and Cu, S-codoped SnO 2were studied by using the first-principles calculation method based on the density functional theory. The corresponding doped SnO2 powders were prepared by sol–gel method, while AgSnO2–Cu and AgSnO2–Cu–S contacts were obtained by powder metallurgy method for experimental verification. No diffraction peaks were associated with Cu and S in the XRD patterns of the doped SnO2 powders, indicating that the doped SnO2 retained the tetragonal crystal structure. The doping formation energy of Cu, S co-doped system was found to be lower than that of Cu single doping system and S single doping system. The bulk modulus, shear modulus and Young's modulus of the co-doped system became lower, the ability to resist compression deformation and shear deformation was also weakened, while its toughness was greatly improved. The hardness of the AgSnO2–Cu–S contact was 103.55 HV, which is less than the hardness of the AgSnO2–Cu contact (112.86 HV). The calculations indicated that Cu, S co-doping could narrow the band gap, reduce the hole effective mass and the acceptor ionization energy, improve the hole mobility, and enhance the conductivity of the material. The electrical contact simulation experiments showed that the conductive properties, arc corrosion resistance and welding resistance of AgSnO2–Cu–S contact were better than those of the AgSnO2–Cu contact. The conductivity of AgSnO2–Cu–S contact was 29.948 mS · m–1, the contact resistance was 1.109 Ωm ; the average arc duration and average arc energy were 1.480 ms and 171.65 mJ, respectively.