Cast sinter technique for producing iron base surface composites

Based on the liquid-sinter theory of powder metallurgy, using the heat of liquid iron during casting, the FeAl2O3, FeZrO2 and FeTiC surface composites, with a thickness of 2–3 mm, were sintered on the surface of cast iron by the addition of ZrO2, Al2O3 or TiC ceramic powder into press blocks, respectively. The structures and compositions of the FeAl2O3, FeZrO2 and FeTiC surface composites were studied with the help of an SEM and an electron probe. The ceramic particles were uniformly dispersed in the iron-alloy matrix. In the FeTiC surface composite layer, the concentration of Ti was relatively stable and consistently retained at a high level, and the concentration of Cr, Mo and Ni took on a gradient distribution and decreased gradually into that of a master-alloy. Increasing the liquid content in the press block and adding an infiltrator, the densification of the surface composite layer and the interface-bond between the surface composite layer and master-alloy can be improved. The cast sinter technique provides the opportunity of producing near-net-shape final components with a metal–ceramic surface composite layer during casting.