High temperature sliding abrasion of a nickel-base alloy and composite

Abstract

In previous work, sliding abrasion by interfacial flint particles was studied for a nickel-base MMC under argon up to 900°C. In the present investigation flint is replaced by corundum and silicon carbide. The hot hardness of the latter is above that of the NiCrAlSi-matrix and the WC/W 2 C particles, which dramatically lowers the wear resistance of the MMC compared to abrasion by flint. Corundum is softer than tungsten carbide and the drop of wear resistance is less severe. In air, WC/W 2 C is readily oxidized, lowering the wear resistance to matrix level. In comparison, Cr 3 C 2 shows lower hot hardness but much better resistance to oxidation. A self-protecting particle layer of material debris and abrasive particles is formed under argon as well as in air, but at 800°C the oxidation of the debris in air entails a highly dense `glaze' layer.