等离子熔覆WC复合厚涂层特性研究

CHARACTERISTICS OF THICK WC COMPOSITE COATING FORMED BY PLASMA CLADDING

将 Ni 基合金和 Ni 包 WC 粉末混合均匀后事先涂覆在低碳钢基体上,通过非压缩弧等离子熔覆设备在低碳钢上制备 Ni 包WC 复合厚涂层。涂层分为三种重量百分比 Ni 包 WC 粉末,分别为5%,10%,15%。应用 X 衍射(XRD)、光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)和显微硬度分析对涂层成分、微观结构和显微硬度进行分析。结果显示涂层和基体之间形成冶金结合,XRD 显示主要的相是γ-Ni 固溶体,以及 Fe_2B、Fe_3B 相和 M_(23)C_6、M_7C_3相。发现等离子熔覆区的显微硬度随着 Ni 包 WC 粉末含量的增加而提高。

The thick Ni-coated WC coating, in a matrix of Nickel-based alloys, was deposited on the low carbon steel by plasma cladding equipment. A pre-placed layer of uniform mixture, Ni-coated WC powder and Nickel -based alloy powder, on the substrate steel was melted at the high temperature of the plasma jet. Different coatings are made with three different weight fractions of 5%, 10% and 15%. The coating composition, microstructure and microhardness were analyzed by X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microscopy （SEM）, energy-dispersive spectrometer （EDS） and microhardness testing. The experimental results show that the metallurgically bond was formed between the coating and substrate. The microstructure of the clad coating consists of dendrite, interdendrite eutectic. SEM shows that the Ni-coated is a very effective method to protect the WC powder. The XRD results show that the phases consist of γ-Ni, carbides, such as M23C6 and M7C3 and bodde, such as Fe2B, Fe3B phases. It was found that the plasma zone has a higher microhardness value with the content of Ni-coated WC powder increasing.