Preparation and Properties of La2O3 Doped AgSnO2Electrical Contact Materials

Abstract:

Ag-SnO2-La2O3 composite powders were prepared by mechanical alloy method with Ag, Sn and La2O3 powder. The composite powders were oxidized, pressed and sintered by combining with oxidation and powder metallurgy processs. The morphology of the composite powders before and after oxidation and their electrical contact materials before and after sintering were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), Vickers hardness tester, metallographic microscope and metal conductivity meter. The results showed that with the increase of Sn content, the resistivity increased but the density decreased after sintering. And the hardness of electrical contact materials was decreased significantly after sintering. When the doping content of La2O3 ranged from 0wt.% up to 3wt.%, the higher the La2O3 doping content, the lower the density of the Ag-SnO2-La2O3 electrical contact material. And with the increase of La2O3 doping content, the resistivity decreased first and then increased for the sintered Ag-SnO2-La2O3 contacts. When the La2O3 doping content was 0.75wt.%, the resistivity of the sintered Ag-SnO2-La2O3 contacts was lowest.

Key words:La2O3 dopant; electrical contact material; sintering; resistivity