Elevated temperature erosion–corrosion of thermal sprayed coatings in chlorine containing environments

A series of hot erosion and erosion–corrosion (E–C) tests was carried out on thermal sprayed coatings, diffusion coatings and boiler steels using a burner-rig type elevated temperature E–C tester in order to evaluate the possibility to utilise thermal sprayed coatings in shielding of boiler components. Test conditions simulated the E–C conditions in the superheater section of a circulating fluidised bed combustor (CFBC). Carbide containing HVOF coatings performed well in erosion tests, as expected. Also diffusion coatings and nickel-based, high-chromium HVOF coatings performed well. In E–C tests in presence of chlorine, nickel-based HVOF coatings performed the best, whereas carbide containing HVOF coatings and diffusion coatings wore away.