In this study, CoCrFeNiSi high entropy alloy (HEA) coating without pores or slag defects was prepared on 304 stainless steel surface by laser cladding. Thermodynamic parameters of CoCrFeNiSi HEA were calculated. Microstructure and phase composition were analyzed by means of scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Comparative studies on hardness, high temperature erosion and oxidation performances were conducted between the CoCrFeNiSi HEA and Stellite-6 Co-based alloy coatings. The results show that laser cladding CoCrFeNiSi HEA coating was composed of single FCC structure. Typical metallurgical bonding between cladding coating and the substrate was formed. Microhardness of CoCrFeNiSi HEA coating reached to approximately 580HV_0.2, which was higher than that of Co-based alloy coating (485HV_0.2). There was little surface hardness reduction at 500, 600 and 700 °C for CoCrFeNiSi and Co-based alloy coatings. Erosion tests were conducted using quartz sand particles at 20, 500, 600 and 700 °C with an impact angle of 30, 60 and 90°, respectively. The HEA coating showed comparatively lower erosion rates than Co-based alloy coating under all test conditions. The erosion morphologies of both coatings showed that ploughing and micro-cutting were the two primary erosion mechanisms at oblique impact angles, while the erosion mechanism was replaced by the formation of craters and platelets at normal impact angles. A dense and continuous oxidation film could form on HEA coating at 700 °C which may protect the coating from erosion at high temperature to some extent.

在这项研究中，通过激光熔覆在304不锈钢表面上制备了无气孔或炉渣缺陷的CoCrFeNiSi高熵合金（HEA）涂层。计算了CoCrFeNiSi HEA的热力学参数。借助配备有能量色散光谱仪（EDS）和X射线衍射仪（XRD）的扫描电子显微镜（SEM）分析了显微组织和相组成。在CoCrFeNiSi HEA和Stellite-6 Co基合金涂层之间进行了硬度，高温腐蚀和氧化性能的比较研究。结果表明，激光熔覆CoCrFeNiSi HEA涂层由单一FCC结构组成。在覆层和基底之间形成了典型的冶金结合。CoCrFeNiSi HEA涂层的显微硬度达到约580HV _0.2高于钴基合金涂层（485HV _0.2）。对于CoCrFeNiSi和Co基合金涂层，在500、600和700°C下表面硬度几乎没有降低。使用石英砂颗粒在20、500、600和700°C下分别以30、60和90°的冲击角进行了侵蚀测试。在所有测试条件下，HEA涂层的腐蚀速率均低于Co基合金涂层。两种涂层的腐蚀形态均表明，在倾斜冲击角下，犁耕和微切割是两种主要的腐蚀机理，而在正常冲击角下，形成的弹坑和血小板代替了腐蚀机理。在700°C的HEA涂层上会形成致密且连续的氧化膜，这可以在一定程度上保护涂层免受高温侵蚀。