Microstructure and High Temperature Corrosion Behavior of Wire-Arc Sprayed FeCrSiB Coating

Nowadays, wire-arc spraying is an attractive technique to deposit coatings for oxidation and corrosion protection. In this study, a new FeCrSiB-cored wire was designed to produce protective coatings for the components used in high temperature environment by wire-arc spraying. The microstructure, phase composition, microhardness, and high temperature corrosion behavior of the new coating were investigated in comparison with a FeCr coating and a commercial NiCrTi coating. The results showed that the FeCrSiB coating was composed of dense lamella with much fewer oxide inclusions than the FeCr and NiCrTi coatings. The microhardness of the FeCrSiB coating was the highest of the three coatings. Thermogravimetric analysis was used to evaluate the high temperature corrosion behavior of the coatings in mixed salt Na2SO4-25% K2SO4 environment at 650 °C under cyclic condition. It showed that the high temperature corrosion resistance of the FeCrSiB coating is significantly better than that of the FeCr coating and approaching to the commercial NiCrTi coating.