Protection of nickel-based alloys against carburization with TiSi-enriched layers

Abstract

The possibility of protecting the nickel-based alloy Hastelloy X against carburization using TiSi-enriched layers is discussed. The TiSi-enriched layers were produced using the chemical vapour deposition reaction xTiCl 4+ ySiCl 4+2( x+ y)H 2→4( x+ y)HCl+TiSi-enriched layer At high carbon activities, kinetic measurements show that the rate of carburization is determined by the diffusion of carbon in a dense adherent TiC layer. An activation energy of −256kJ mol −1 was calculated from an Arrhenius plot of the parabolic rate constant k p.