Effects of Some Light Alloying Elements on the Oxidation Behavior of Fe and Ni-Cr Based Alloys during Air Plasma Spraying

This study investigates the effect of alloying additions on the oxidation behavior of iron (Fe) and nickel-chromium (NiCr) powders during atmosphere plasma spraying. The chemical composition and phases of oxides in the particles as well as in the coatings are assessed for different powder mixtures and spraying parameters. The results show that oxygen content can be significantly reduced by adding silicon (Si) and boron (B) to iron powders and Si, B, and carbon (C) to NiCr. The preferential oxidation and subsequent vaporization of Si, B, and C from the surface of the sprayed particles are believed to play a major role in controlling oxidation in the APS process.