Preparation Of AgMeO Contact Materials And Study Of Anti-arc Erosion Performance

Electrical contact is the key component of relays.Its performance affects the reliability of electrical power system greatly. Arc discharge occurrs when contacts make or break current.Contact erosion caused by arc discharge has important effects on the life-span and reliability of contacts.Since insufficient theoretic study on arc erosion,selecting contact materials mainly depends on experiments,which is quite expensive and time-consuming. For improving the new contact material development,it is necessary to establish arc erosion model to reveal the relationship between arc erosion and material properties.So study of anti-erosion performance of different contact materials is helpful to select excellent contact materials which would have a longer working life-span.In this paper the equation which related circuit parameters to heat source boundary condition was derived. The transient temperature fields of composite materials were calculated by FLUENT and MATLAB. Combining with material properties of several Ag-based contact materials,their areas of molten pool were calculated. The results suggested that the areas of Ag,AgNi10,AgSnO2 and AgZnO were nearly equal. Comparing with the practical areas of contact,they were much smaller.But there were big gaps between the theoretical number and the practical.The addition of second phase dispersed arc erosion and avoided severe erosion in the same position.At the same time,the second phase enhanced the viscosity of molten pool. The addition of MeO can get both effects to a larger extent. Therefore,it was predited that AgMeO material can exhibited the best anti-arc erosion performance.The experiments for anti-arc erosion performance of AgNi0.15,AgNi10 and AgSnO2 contacts were carried out under inductive,resistive and lamp loads at the low-voltage.And the results verified the prediction. And the surface microstructures and element compositions were examined by SEM and EDS.So based on these conclusions,AgZnO materials were fabricated by powder metallurgy. Composition of 90wt%Ag and 10wt%ZnO were used to prepare the sintered body.The sintering temperature were 830℃,840℃,850℃,860℃and 870℃, it was found that 860℃was the best sintering temperature. AgSnO2 material was fabricated by internal oxidation method.The oxidation velocity decreased when oxidation was going on.The oxygen pressure and oxidation temperature were the key point to internal oxidation process.