The formation of disordered intermetallic phase during the solid-state interaction of WC with Ir

Abstract

A relatively simple approach based on mixing WC and iridium powders, followed by heating to 1300–1600 °C in inert atmosphere, was proposed to synthesize refractory intermetallics in the tungsten – iridium system. The peculiarities of the solid-state interaction in the WC-Ir system were studied within the 1000–1600 °C temperature range using a set of modern analytical techniques. Intensive solid-state interaction in the WC – Ir system starts at 1300 °C. It was stated that this interaction can be described by two stages in the 1300–1600 °C temperature range. The first stage is the formation of Ir-rich disordered WxIr1-x solid solution with constant average composition W0.265Ir0.735. The second stage is the interaction of the obtained WxIr1-x solid solution with residual component (Ir or WC) that leads to the shift of the WxIr1-x phase composition on one side or the other in dependence on type of residual component. No ordered intermetallic phases are formed in the 1300–1600 °C temperature range. In the course of the solid-state reaction, free carbon is released as graphite-like phase on the surface of the intermetallic product.