AbstractThe layer morphology and structure resulting from the glow discharge plasma chromising of steels containing 0·22, 0·45, 1·0, and 1·2%C are discussed. The growth kinetics of chromium and carbide layers has been investigated; the relationship between layer thickness and chromising time follows a parabolic law. An equation for growth of the surface carbide layer as a function of matrix carbon activity and chromising time has been derived. The calculated and measured values are in good agreement. It is shown that ion bombardment accelerates chromising.