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以304不锈钢为基材,Ti-45Al-8Nb金属间化合物为电极,制备电火花沉积涂层,并研究其在锌液中的腐蚀行为。结果表明,涂层与基体呈冶金结合,是电极材料与基体材料剧烈重熔扩散的产物。相比304不锈钢,涂层样品的耐熔锌腐蚀性能显著提升,表现为孕育型腐蚀,孕育期为15天。涂层的腐蚀最初发生于样品的棱角处,属于典型的裂纹-瓦解机制。涂层碎片与锌液发生少量元素扩散,生成富Fe、Al的腐蚀产物。依据润湿的相关理论,讨论了涂层中原生裂纹对涂层耐熔锌腐蚀性能的影响。如果适当改善沉积工艺,减少涂层裂纹,有望延长涂层的使用寿命。
Using 304 stainless steel as substrate and Ti-45Al-8Nb intermetallic compound as electrode, EDM coating was prepared and its corrosion behavior in zinc solution was studied. The results show that the coating is metallurgically bonded with the substrate, which is the product of the severe remelting and diffusion of the electrode material and the matrix material. Compared with 304 stainless steel, the corrosion resistance of the coating samples significantly improved zinc corrosion, showing pregnant-type corrosion, the incubation period of 15 days. Corrosion of the coating initially occurs at the corners of the sample and is a typical crack-disintegration mechanism. A small amount of elemental diffusion occurs between the coating fragments and the zinc solution, resulting in the corrosion products rich in Fe and Al. According to the related theory of wetting, the influence of the primary crack in the coating on the corrosion resistance of the coating to molten zinc was discussed. If properly improve the deposition process, reduce the coating cracks, is expected to extend the life of the coating.