微弧强化表面纳米WC/Co涂层的制备及性能研究

Research on Preparation and Properties of Nano WC/Co Coating on Micro-arc Enhanced Surface of NiCrMo White Iron

采用超音速火焰喷涂技术在Ni Cr Mo白口铸铁微弧强化表面制备纳米WC/Co涂层。采用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度仪和自动划痕仪对该涂层的组织结构、物相、硬度和结合强度进行分析。结果表明:通过超音速火焰喷涂可制备内含均匀的粒径在0.1~0.2μm的纳米颗粒涂层,该涂层是由WC、Co和少量的W2C相组成,这些纳米颗粒实际是喷涂过程中未熔粉末中的纳米颗粒;基体与涂层间的结合强度和表面平均硬度分别为46.6 N和1577.2 HV,都高于基体与非纳米涂层的结合强度和表面硬度。

Nano WC/Co coating was prepared on the micro-arc enhanced surface of Ni Cr Mo white cast iron by high velocity oxygen fuel spraying. The microstructure, phase, hardness and bonding strength of the coating were analyzed by SEM, XRD, microhardness tester and automatic scratch tester. The results show that the nanostructured coating with uniform particle size in the range of 0.1-0.2 μm could be prepared by the high velocity oxygen fuel spraying, which is composed of WC, Co and a small amount of W2C. These nanoparticles are actually unmelted nano powders during the process of spraying.The bonding strength between the substrate and the coating and the average surface hardness are 46.6 N and 1577.2 HV,respectively, which are higher than that between the matrix and no nanostructured coatings.