HVAF 喷涂超细 WC-10Co-4Cr 粉末涂层的耐腐蚀性研究

对比研究超细和常规粒度 WC-10Co4Cr 粉末喷涂制备涂层的性能，根据显微形貌、力学性能与电化学特 性比较两种涂层的耐腐蚀性并分析机理。在 304 不锈钢基体上，利用空气助燃高速 (High Velocity Air Fuel, HVAF) 热喷涂技术制备 WC-10Co-4Cr 涂层。采用 SEM 和 XRD 分析了涂层的物相组成和显微形貌，采用维氏硬度仪和 万能拉伸试验机分别测试了涂层的显微硬度与结合强度以表征力学性能，在质量分数为 3.5% 的 NaCl 溶液中对 涂层进行电化学分析。结果表明：两种 WC-10Co-4Cr 粉末涂层均具有优异的耐腐蚀性能，超细粉末涂层自腐蚀 电位 (-0.199 V) 高于常规粉末粒径涂层 (-0.267 V)；超细粉末粒径涂层腐蚀电流密度 (1.996×10-7 A/cm2 ) 小于常规 粉末粒径涂层 (3.123×10-6 A/cm2 )，对基体能起到良好的保护作用。超细粉末与常规粉末 WC-10Co-4Cr 涂层电位 腐蚀的机理主要是 WC 与粘结相的电偶腐蚀、Cl - 对涂层表面钝化膜的破坏引起的孔蚀，腐蚀机理基本一致，主 要差异在于，超细粉末涂层的致密度更高，组织更加均匀提高了涂层的耐腐蚀性。

Study on Corrosion Resistance of HVAF Sprayed Ultra-thin WC-10Co-4Cr Coatings

The performance of ultrafine and conventional WC-10Co-4Cr coatings was investigated. The corrosion resistance of the two coatings was compared according to the microscopic morphology, mechanical properties and electrochemical properties, and the mechanism was analyzed. WC-10Co-4Cr coating was deposited by High Velocity Air Fuel (HVAF) thermal spraying on 304 stainless steel substrate. The phase composition and micromorphology of the coating were analyzed by SEM and XRD. The microhardness and bonding strength of the