Preparation, characterization and densification studies of W-Ag nanocomposites produced by chemical route

Abstract

W-Ag has applications in a wide range of cutting-edge fields, counting heat sinks and microwave absorbers for micro—electronic components, electric arc ends, and filaments for welding processes, electrical contacts, and durable electronic connections. Chemical methods provide a number of benefits, including improved purity, and controlled particle size. The present study focused on the fabrication of W-Ag nano composites using chemical synthesis. W-Ag nanocomposites with average size less than 50 nm were synthesized using Tungsten hexacarbonyl (W(CO)6, and silver acetate (CH3-COOAg) as metal precursors in the present study. The W-Ag composites were sintered using conventional sintering. X-ray diffraction studies of as-prepared powders showed amorphous W-phase and FCC Ag, while sintered W-Ag composites exhibited crystalline BCC W and FCC Ag phase. The effect of sintering temperature on relative density and mechanical properties of W-Ag sintered compacts was investigated. Relative density in excess of 97.6%, 98.2% and 98.8% was achieved for W-20.3 wt.% Ag, W-30.1 wt.% Ag and W-39.8 wt.% Ag composites on conventional sintering at 1000°C for 1 h. Vickers hardness of 364 ± 10 and 320 ± 8 Hv and 279 ± 6 were achieved for W-20.3 wt.% Ag, W-30.1 wt.% Ag and W-39.8 wt.% Ag composite compacts respectively. The hardness value of W-Ag composites decreased with an increase in Ag content. The combination of properties realized in this study renders the composites suitable for automotive and heat sink applications.