HVAF喷涂Inconel 625涂层在生物质发电环境的高温腐蚀行为

The combination of HCl gas and alkali-chloride makes the hot corrosion rate of the heated side components in the straw incineration much faster than that in the conventional coal fired boiler condition. It is demonstrated that though arc surfacing Ni-based corrosion resistant layer can effectively improve the lifetime of the heat resistance steel tubes, but there exists lots of problems such as low work efficiency, cannot be in-sited used for the boilers and hot deformation of pipelines. High velocity air fuel (HVAF) spray was applied on TP347H heat resistance steel to evaluate the corrosion protection effect of the present coating. Long-term (550℃ for 500 h) hot corrosion was performed for both the bare and coated TP347H steel specimens and the hot chlorine-containine corrosion protection effect of HVAF Inconel 625 coating was verified. The microstructure observation results show that the HVAF coating reveals a dense microstructure with porosity as low as 0.72% and well bonds to the substrate. The corrosion rate test result indicates that after coated with HVAF Inconel 625, a dramatic 7.6 times decrease in the corrosion rate is achieved for TP347H steel and its corrosion resistance is significantly reduced. The erosion test result indicates that the erosion resistance of the HVAF Inconel 625 coating is lower at the beginning due to the peel-off of surface convex particles but is comparable with that of the TP347H steel substrate in the stable state.