Preparation of perovskite La1-xSrxCoO3-δ Powders and its application in Silver based electrical contact materials

Abstract:

The LSCO_p and LSCO_wpowders were synthesized by sol-gel method. And then Ag-LSCO_pand Ag-LSCO_w electrical contact composites were fabricated by high-energy ball milling and sintering process with LSCO powders as the second reinforcement phase. The effects of pH and pre-treated sol temperature on the microstructure of LSCO powder were optimized. The effects of molding pressure and sintering temperature on the electrical and mechanical properties of Ag-LSCO contacts were investigated. The microstructure and phase of LSCO powders and Conductivity and hardness characteristics of the Ag-LSCO electrical contact material were tested by scanning electron microscopy (SEM), X-ray diffractometer(XRD), D60K digital metal conductivity meter and HVS-1000 digital microhardness tester. The results showed that LSCO_p was obtained at pH= 9.5 and sintering temperature of 700℃ for 8 h when using single citric acid as gelling agent, but LSCO_w was obtained with citric acid and EDTA used as complex gelling agents. Ag/LSCO_w electrical contact materials were prepared with the molding pressure of 1100 MPa, sintering temperature of 900℃ and sintering time of 6h. And when using LSCO_w powder as the second reinforcement phase, Ag-LSCO_w electrical contacts showed lower resistivity than that of Ag-LSCO_p.