La2O3掺杂AgSnO2电接触材料的制备及性能研究

以Ag、Sn、La₂O₃粉为原料,采用机械合金法制备复合粉体。结合氧化法与粉末冶金工艺,对复合粉体进行氧化、压制、烧结。采用扫描电镜(SEM)和能谱仪、硬度计、金相显微镜、金属电导率测量仪等对复合粉体氧化前后的形貌以及电接触材料烧结前后的性能进行表征。结果表明：烧结后,电接触材料硬度较于烧结前明显下降。同时电接触材料随Sn含量增大,电阻率升高,密度反而下降。在一定的La₂O₃(0wt.%、0.75wt.%、1.5wt.%、2.25wt.%、3wt.%)含量范围内,La₂O₃掺杂量越高,密度越低。同时电接触材料经烧结后,随La₂O₃含量增加,其电阻率先降后升,在La₂O₃含量为0.75wt.%时,电接触材料的电阻率最低。

Preparation and Properties of La2O3 Doped AgSnO2Electrical Contact Materials

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.