Research On The Preparation And Properties Of Ag-ZnO-TiC Electrical Contact Material

Ag-ZnO electrical contact material is a kind of environmentally friendly material,because of the high melting point and high decomposition temperature of ZnO,they gradually replaced the toxic Ag-CdO materials.Currently,the main preparation of Ag-ZnO electrical contact material are powder metallurgy and internal oxidation,Ag-ZnO electrical contact materials prepared by powder metallurgy method have low density,and the coarse particles of ZnO lead to the poor of resistance to welding and arc erosion of Ag-ZnO electrical contact materials,but Ag-ZnO electrical contact materials prepared by internal oxidation method show homogeneous microstructure.Therefore,Ag-ZnO electrical contact materials for the preparation of the study have important significance.TiC is a kind of high melting point(3160?),high hardness and good electrical and thermal conductivity,in aspect of enhancing the stability and reliability of electric switch have certain effect,the TiC for the influence of the organization and performance of Ag-ZnO electrical contact materials have not been reported,so the study of preparation and properties of Ag-ZnO-TiC has the innovative significance.In this paper,ZnO powder was prepared by direct precipitation method,and Ag-ZnO composite powder was prepared by powder mixture-electromagnetic stirring method,High desity of Ag-ZnO-TiC electrical contact materials were prepared by pressing-sintering-resintering-rolling,using a variety of characterization techniques(SEM,XRD,EDS,etc)on Ag-ZnO-TiC electrical contact materials in the process of organizational changes and performance of characterization testing,ultimately got the following conclusions:(1)When regard Zn(NO3)2 as the zinc source,H2C2O4·2H2O as precipitant,and Zn(NO3)2 solution was 0.1 mol/L,H2C2O4 solution was 0.3 mol/L,the solvent for the reactants were distilled water,the reaction temperature was room temperature,the annealing temperature was 500?,finally,the bulk ZnO powder with a diameter range from 2?m to 4?m was obtained.(2)Ag-ZnO-TiC composite powder had been prepared by mechanical mixing and ultrasonic oscillation,and Ag combined with ZnO and TiC closely.By pressing sintering preparation of Ag-ZnO-TiC block,through the study had found that when the molding pressure for 300MPa,the holding time of 11 Os,the first sintering temperature is 750?,the secondary temperature is 700?,with high density of Ag-ZnO-TiC block had been prepared.The Ag-ZnO-TiC sheet can be obtained through annealing during each pass,it proved that the material we prepared has excellent workability.(3)Ag-ZnO electrical contact material by adding TiC had made the breakdown strength significantly increased,the breakdown strength of the content of TiC with 1%?0.5%compared Ag-ZnO electrical contact material without TiC increased by 62%and 55%;Ag-ZnO electrical contact material by adding TiC had scattered the arc erosion area.High density of Ag-ZnO-TiC electrical contact material compared to the low density of Ag-ZnO-TiC(1%)had more excellent arc erosion resistance.