铜电极表面电火花沉积ZrB_2-TiB_2复相涂层

ZrB_2-TiB_2 composite coating on surface of copper electrode by electrospark deposition

采用粉末冶金法制备Zr B2-Ti B2复相材料熔敷棒,并通过电火花沉积工艺在铜电极表面制备Zr B2-Ti B2复相涂层。通过扫描电镜结合能谱分析研究了涂层的显微结构和元素分布,利用X射线衍射和显微硬度测试对涂层的物相组成与显微硬度进行检测。结果表明:直接熔敷Zr B2-Ti B2复相涂层致密性较差,且存在较多裂纹,与基体有明显分层,涂层物相为Cu、Zr B2和Ti B2;在预沉积Ni层(Ni层)上后沉积Zr B2-Ti B2,所得的多层涂层具有较好的致密性,且涂层与基体间无分层;中间层有Ti、Zr、Cu元素的扩散,说明涂层与基体为冶金结合;Zr B2-Ti B2复相涂层硬度为900 HV0.05稍高于多层涂层硬度(800 HV0.05)。

ZrB2-TiB2 composite rods were prepared by powder metallurgy technique,and the Zr B2-Ti B2 composite coating was deposited on the surface of copper electrodes through electrospark deposition process. Microstructure and elements distribution of the coating were characterized by scanning electron microscopy and energy dispersive spectrometer. Phases and hardness of the coating were examined by X-ray diffraction and microhardness tests. The results show that the Zr B2-Ti B2 composite coating exhibits poor density and extensive cracking and delamination are observed for the coating,in which major phases are Cu,Ti B2 and Zr B2. When the Zr B2-Ti B2 composite coating is deposited on the copper electrodes precoated with Ni,no cracks and delamination are found in the multilayer coating of Ni +( Zr B2-Ti B2). Diffusion of elements is observed in the multiayer coating,indicating that the coating-susbstrate interface by metallurgical bonding forms. The average hardness of the Zr B2-Ti B2 composite coating is approximately 900 HV0. 05 and higher than that of the Ni +( Zr B2-Ti B2) multilayer coating( 800 HV0. 05).