An evaluation of the endurance of chromized and plated chromium coatings in a hot gas erosion atmosphere

A comparison was made of the endurance of plated chromium and chromized coatings in a high temperature erosion atmosphere, produced by burning propellants in an erosion test apparatus. The substrate materials used for these coatings were a nickel-base alloy (Inconel 718), an FeNi-base alloy (CG-27), H11 tool steel and CrMoV steel. The erosivity was obtained from weight loss determinations. Chromizing provides a better erosion-resistant surface for Inconel 718 than chromium plating does, whereas chromium plating provides a better resistance to erosion for CG-27, H11 and CrMoV steels than chromizing does. Optical metallography, scanning electron microscopy and energy-dispersive analysis with X-rays confirm these findings.