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采用高速电弧喷涂工艺在低碳钢基体表面制备了FeNiCr/Cr3C2和NiCrTi两种电弧喷涂涂层。通过光学显微镜对涂层的显微组织进行了观察研究。试验选用摩尔比为7:3的Na2SO4+K2SO4饱和水溶液涂刷在涂层表面,在700℃的条件下进行了156 h的热腐蚀试验。通过腐蚀动力学测试对电弧喷涂涂层的抗热腐蚀性能进行了评估。采用了X射线衍射,扫描电镜和能谱分析技术对热腐蚀机理进行了探讨。结果表明,两种电弧喷涂涂层具有致密的层状结构,涂层中含有少量空隙。在涂层表面生成的连续致密的氧化膜使得NiCrTi涂层具有良好的抗热腐蚀性能。FeNiCr/Cr3C2涂层则遭受了较严重的氧化腐蚀和硫化腐蚀,并且有内硫化物析出,抗热腐蚀性能较差。
High-speed arc spraying process was used to prepare two kinds of arc spraying coatings of FeNiCr / Cr3C2 and NiCrTi on the surface of low carbon steel substrate. The microstructure of the coating was observed by light microscopy. In the experiment, a saturated aqueous solution of Na2SO4 + K2SO4 with a molar ratio of 7: 3 was used to coat the surface of the coating. The hot corrosion test was carried out at 700 ℃ for 156 hours. The hot corrosion resistance of arc sprayed coatings was evaluated by the corrosion kinetics test. X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy were used to investigate the mechanism of hot corrosion. The results show that the two kinds of arc spray coating has a dense layered structure, the coating contains a small amount of voids. The continuous dense oxide film formed on the surface of the coating made the NiCrTi coating have a good resistance to hot corrosion. FeNiCr / Cr3C2 coating suffered more serious oxidation and sulfide corrosion, and sulfide precipitation, thermal corrosion resistance is poor.