Enhancing High Temperature Erosion-Corrosion Resistance of SA213-T91 Steel by HVOF Sprayed Nano-Structured Ni-20Cr Coating

This study assesses the fireside erosion-corrosion behavior of nanostructured NiCr coatings in a power plant boiler operating at 750 °C. In the experiments, Ni-20Cr nanocrystalline powder was synthesized by ball milling and deposited on T91 boiler steel substrates by HVOF spraying. Coated and uncoated steel specimens were thermally cycled in the superheater zone of a coal fired boiler. After 15 heating and cooling cycles, the specimens were examined and erosion-corrosion kinetics were established via weight-change and thickness-loss measurements. The results show that the nanostructured coatings reduced the erosion-corrosion rate of T91 steel by 85%.