摘要:
采用等离子喷涂技术在TiAl合金表面制备了MCrAlY涂层,并用激光重熔工艺对涂层进行处理,研究了TiAl合金、等离子喷涂MCrAlY涂层及激光重熔MCrAlY涂层850℃下75%Na2SO4+25%NaCl(质量分数)混合盐浸泡热腐蚀性能,分析了不同试样的热腐蚀破坏机理,并讨论了激光重熔处理对涂层热腐蚀性能的影响.结果表明,等离子喷涂MCrAlY涂层能显著提高TiAl合金的耐热腐蚀性能,经过激光重熔后可进一步提高其耐热腐蚀性能.MCrAlY涂层在高温熔盐中的热腐蚀发生的是表面氧化反应和内部硫化反应,主要生成Al2O3,Cr2O3,NiO,NiCr2O4,Ni3S2及CrS等腐蚀产物.
Abstract:
The MCrAlY coatings were prepared by plasma spraying on TiAl alloy surface, laser remelting experiment had been carried out and the hot corrosion resistance of TiAl alloy, plasma-sprayed and laser-remelted MCrAlY coatings in 5%Na2SO4+25% NaCl(mass fraction) molten salt at 850℃ were researched. The hot corrosion failure mechanisms of three kinds of materials were analyzed and the influence of laser remelting on hot corrosion behavior of plasma-sprayed MCrAlY coating were discussed. The results show that the plasma-spayed MCrAlY coating has better oxidation resistance than the original TiAl alloy, and the laser-remelted coating has the best oxidation resistance. The hot corrosion of MCrAlY coating included surface oxidation and internal sulfide, and produced Al2O3, Cr2O3, NiO, NiCr2O4, Ni3S2 and CrS et al.
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