Cast sinter technique for producing iron base surface composites

Abstract

Based on the liquid-sinter theory of powder metallurgy, using the heat of liquid iron during casting, the FeAl 2O 3, FeZrO 2 and FeTiC surface composites, with a thickness of 2–3 mm, were sintered on the surface of cast iron by the addition of ZrO 2, Al 2O 3 or TiC ceramic powder into press blocks, respectively. The structures and compositions of the FeAl 2O 3, FeZrO 2 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.