Preparation and Electrical Life Performance of Multi-component Modified Ag/SnO2 Electrical Contact Materials by Internal Oxidation Method
In order to explore the impact of the type and content of the modified components on the preparation process,microstructure,microhardness,temperature rise and electrical life of the modified Ag/SnO2In2C3 contact materials,the modified AgSnIn alloys were synthesized by medium-frequency smelting and casting process,and then the corresponding Ag/SnO2In2O3 contact materials were prepared by internal oxidation method.The AC-4 electrical life type testing platform was used to evaluate the temperature rise and electrical life performance of the materials.The results show that the optimum parameters of internal oxidation process of the modified Ag/SnO2In2O3 materials are 700 ℃/5 MPa/48 h.Compared with the binary modification of Ni,Cu or Zn,there exists larger micro-strain in the Ni-Cu-Zn ternary modified AgSnIn alloys,and the microhardness of the corresponding modified Ag/SnO2In2O3 material increases first and then decreases sharply with indium content decreasing.The modified AgSnIn alloy,composed of 0.47wt％Ni,0.4wt％Cu,0.43wt％Zn and 2.lwt％In,could achieve complete internal oxidation.The corresponding modified Ag/SnO21n2O3 material presents the optimum microhardness(1382.49 MPa),the longest cycle number(28989 operations)and an appropriate temperature rise(43.69 K),which is attributed to some larger micro-strain(1.9×10-4)and grain boundary structure with strengthening effect.The comparison analysis reveals a positive correlation has been established between the electric life cycle number and the microhardness of the modified Ag/SnO2 material within In element content range from 2.lwt％to 3.lwt％,which provides a new idea for the formulation design and electric life performance prediction of the Ag/SnO2 contact material.
Ag/SnO2 electrical contact materialsinternal oxidationmicro-strainmicrohardnesselectrical life performance
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