Materials Science Forum, Vol.369-3, 475-482, 2001
High temperature erosion-corrosion of superheater materials and coatings in chlorine containing environments
A series of elevated temperature erosion and erosion-corrosion (E-C) tests were carried out on thermally sprayed coatings, diffusion coatings and boiler steels using a burner rig-type elevated temperature E-C tester. Test conditions simulated E-C conditions in the superheater section of a circulating fluidised bed combustor. The gas temperature was 850 degreesC and the tubular samples were internally cooled with air to 550 degreesC. Quartz sand (50-500 mum) was used as erosive media. Potassium chloride (KCl, 0.1%) was added to quartz in E-C tests. Cr3C2-NiCr HVOF coating performed better in hot erosion tests than metallic HVOF and arc-sprayed coatings. Cr- diffusion treatment improved erosion resistance of steel significantly. In E-C test the Cr3C2-NiCr HVOF and diffusion chromium coatings were destroyed and the dense, metallic HVOF coating performed best. Arc-sprayed coating and steel exhibited higher material loss.