Preparation And Properties Of Nano-doped Ag/SnO₂ Contact Material

Antimony-doped tin dioxide powder（ATO）was synthesized by water-based sol-gel method.The optimization processing parameters of ATO sol and the effects of antimony doped content(n_Sn/n_Sb)on particle size of ATO sol and the morphology and phase structure of sintered ATO powders were investigated.Ag/ATO electrical contact materials were prepared by high energy ball milling and powder metallurgy methods.The effects of sintering temperature and sintering time on hardness,density,resistivity and other properties of Ag/ATO electrical contact material were also discussed.The morphology,phase structure and chemical state of the powders were characterized by X-Ray diffractometer（XRD）,energy disperse spectroscopy（EDS）,scanning electron microscope（SEM）,transmission electron microscope（TEM）and X-ray photoelectron spectroscopy（XPS）.The results show that the optimal parameters of ATO sol are as follows:sol concentration=0.1mol/L,bath temperature=50℃,pH=7 and n_Sn/n_Sb=90/10.The phase structure of ATO powder has no relation with the ratio n _Sn/n_Sb.XRD and XPS analysis confirmed Sb ions have been successfully incorporated into the SnO₂ lattice in the form of Sn⁴⁺,Sb⁵⁺and Sb³⁺.Compared to conventional Ag/SnO₂ electrical contact materials,doped Sb elements help to improve the hardness,density and electrical properties of Ag/SnO₂ electrical contact material.Data analysis showed that under the sintering condition of 850℃for 4h,Ag/ATO electrical contact material has the optimum values of hardness(87 HV_0.5),density(9.57 g·cm^-3),resistivity values（3.14μΩ·cm）.