Synergistic Effects of Silicon and Phosphorus on Sintering of Ferrous Metal Powder Compacts

Abstract

The sintering and alloying behaviour of ferrous metal powder compacts has been studied using dilatometry and scanning electron microscopy. Two binary compositions, Fe-3 wt % Si and Fe-3 wt% Fe3P (0.46 wt % P), and one ternary, Fe–3 wt % Si–3 wt % Fe3P were compared. In the ternary compacts it was found that phosphorus and silicon behaved synergistically. Phosphorus strongly enhanced the alloying which took place between iron and silicon at temperatures in the range 900–1100°C. Alloying with silicon, on the other hand, greatly enhanced the sintering (neck growth and shrinkage) or iron-phosphorus by rendering the alloy fully ferritic at all solid temperatures and thereby promoting higher rates of selfdiffusion in the alloy.