High velocity oxy-fuel (HVOF) thermal spray coatings of TiA1 and several A1- as well as A1-Ti-cementation coatings were applied on ferritic and austenitic stainless steels and tested in a reducing sulfidizing atmosphere, under metal dusting conditions and in a sulfidizing carburizing atmosphere at a temperature of 700°C. The tests were run isothermally for up to 1000 h. The thermal spray coatings and the Al-diffusion coatings were corrosion resistant in purely sulfidizing
and in metal dusting atmospheres. If a sulfidizing and carburizing environment is present only the A1-Ti-codiffusion coating can provide protection over the whole test duration.
Keywords: high temperature corrosion, protective coatings, reducing sulfidizing atmosphere, carburizing atmosphere, metal dusting, refinery residues