电弧喷涂镍基涂层组织与高温氧化行为研究

In order to improve the high-temperature oxidation behavior and abrasive resistance of the heat exchanger tubes, the new NiCrB cored-wires with two different boron contents were designed and deposited coatings by wire arc spraying technology. The microstructures, high-temperature oxidation behavior and microhardness of the NiCrB coatings were investigated in comparison with the commercial NiCrTi coating. The results show that the NiCrB coatings exhibited dense lamella structures with fewer oxide inclusions than the NiCrTi coating. The porosities of all the Ni-based coatings were around 3%. The microhardness of NiCrB coatings were higher than that of NiCrTi coating, thus leading to its superior wear resistance. Thermogravimetric analysis was used to evaluate the high-temperature oxidation behavior of the Ni-based coatings at 800℃ under cyclic oxidation condition. It showed that the NiCrB coating with lower boron content exhibited a much better high-temperature oxidation resistance than that of substrate and approached to the commercial NiCrTi coating.