WC颗粒对WC-10Co-4Cr涂层结构演变与性能的影响

Effect of WC Particles on the Structure Evolution and Properties of WC-10Co-4Cr Coating deposited by Plasma Spraying

摘要:

为提高不锈钢表面的抗腐蚀耐磨损性能,利用等离子喷涂的方法制备了两种晶粒尺寸的WC-10Co-4Cr涂层,采用SEM、XRD表征了涂层的物相结构,在不同温度下进行了摩擦磨损试验,研究分析了晶粒对涂层微观结构与摩擦性能的影响。研究表明：相比较,纳米WC-10Co-4Cr涂层微观结构中包含WC、W₂C,还存在Co/Cr(W, C)的γ相,未发现微米涂层中析出的W2C将沿WC颗粒表面外延生长的包覆结构,而且纳米团聚粒子更容易沿扁平粒子边界收缩,明显减少了粒子内部的垂直贯穿裂纹。在室温和200℃时,纳米WC-10Co-4Cr涂层摩擦系数与平均磨损率均优于微米涂层。与微米涂层相比较,纳米WC-10Co-4Cr涂层在室温磨损的根源在于硬质颗粒诱发的犁削磨损,在200℃时为以粘着磨损为主的微域犁削相结合的磨损模式。并在3.5%NaCl溶液中将1Cr18Ni9Ti基体的腐蚀电位由-617mV提高到-335~-290mV,降低了腐蚀倾向。

Abstract:

In order to improve the wear resistance of stainless steel surface, WC-10Co-4Cr coating with two grain sizes was prepared by plasma spraying. The phase structure of the coating was characterized by SEM and XRD. Friction and wear test, the influence of grain on the microstructure and friction properties of the coating was studied. The results show that the microstructure of nano-WC-10Co-4Cr coating contains WC and W₂C, and there is also γ phase of Co/Cr(W, C). It is not found that the W2C precipitated in the micron coating will follow the surface of WC particles Epitaxial growth of the coating structure, and nano-agglomerated particles more easily along the flattened particle boundary contraction, significantly reducing the particles within the vertical through cracks. At room temperature and 200℃, nano-WC-10Co-4Cr coating friction coefficient and the average wear rate are better than the micron coating. Compared with the micron coating, nano-WC-10Co-4Cr coating at room temperature wear is rooted in the hard particles induced plow wear, at 200℃ for the wear-resistant micro-domain plowing combined wear mode The And the corrosion potential of 1Cr18Ni9Ti matrix increased from -617mV to -335 ~ -290mV in 3.5% NaCl solution, which decreased the tendency of corrosion.