Silver-metal oxide type electrical contact materials by mechanical alloying

摘要

Electrical contacts grade composite powders of Ag-CdO and Ag-ZnO are synthesized by conventional powdermetallurgy (PM) route of mixing of silver and metal oxide powderparticles and by the novel technique of Mechanical Alloying (MA)involving high energy attrition milling of silver and metal oxidepowder particles in an attritor. Both blended and mechanicallyalloyed powders are characterized by x-ray diffraction (XRD),particle size analysis and atomic absorption spectrometry (AAS).The composite powders so obtained are pressed, sintered,repressed and hot-pressed to get high density compacts and areevaluated for properties viz. density, hardness, electricalconductivity and microstructure. The compacts of MA route arefound to offer an excellent combination of properties in terms ofhigh hardness, near to theoretical density, good electricalconductivity and microstructure with highly uniform dispersion ofoxide phase in silver matrix. The MA process appear to be simple,clean and economical also.