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    等离子熔覆硼化物覆层的耐蚀性

    Corrosion Resistance of Boride Cladding by Plasma Cladding

    • 摘要: 采用等离子熔覆技术将自制的Mo-Fe-B-Cr药芯焊丝熔覆在316L不锈钢表面制备了硼化物覆层,通过扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和显微硬度计对硼化物覆层的组织、成分、物相和显微硬度进行分析,并通过电化学试验和中性盐雾试验对覆层的耐蚀性进行研究。结果表明:硼化物覆层主要由Mo2FeB2、(Mo,Fe,Cr)3B2、α-Fe和Fe23(C,B)6组成,其显微硬度约为不锈钢基体的3.9倍;在中性环境中硼化物覆层的耐蚀性略低于316L不锈钢,而在酸性环境中硼化物覆层的耐蚀性要优于316L不锈钢;在中性盐雾腐蚀过程中,硼化物覆层表面会生成致密性良好的钝化膜,从而使覆层具备良好的耐蚀性。因此,硼化物覆层在拥有高硬度的同时还兼具良好的耐蚀性。

       

      Abstract: The boride cladding was prepared by plasma cladding technique on the surface of 316L stainless steel with Mo-Fe-B-Cr flux-cored wire. The microstructure, composition, phase and micro-hardness of the boride cladding were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and micro-hardness meter. The corrosion resistance of the cladding was studied by electrochemical test and neutral salt spray test. The results show that the boride cladding was mainly composed of Mo2FeB2, (Mo, Fe, Cr) 3B2, α-Fe and Fe23(C,B)6, and the micro-hardness of the cladding was about 3.9 times that of the stainless steel substrate. The corrosion resistance of the boride cladding in neutral environment was slightly lower than that of 316L stainless steel; and the corrosion resistance of the boride cladding in acidic environment was better than that of 316L stainless steel. In the process of neutral salt spray corrosion, a good dense passivation film formed on the surface of boride cladding, giving a good corrosion resistance of the cladding. So the boride cladding had both high hardness and good corrosion resistance.

       

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