等离子熔覆ZrB_2-ZrC/Fe复合涂层组织及耐磨性

采用等离子熔覆技术,以Zr、Fe、B_4C混合粉末为原料,在Q235低碳钢表面原位反应合成了ZrB_2和ZrC增强的Fe基复合涂层,分析了ZrB_2-ZrC/Fe涂层的物相组成和组织结构,并进行了硬度、耐磨性对比试验,探讨了物相和组织结构的形成过程及磨损机制。结果表明:涂层主要物相为ZrB_2、α-Fe、ZrC、Fe_2B和Fe_3C,其中ZrB_2呈现针棒状、花瓣状,ZrC呈现规则的颗粒状;随着原始粉末中(Zr+B_4C)含量的增加,增强相ZrB_2和ZrC含量增多,尺寸变大,ZrB_2-ZrC/Fe涂层与Q235钢基体之间结合紧密,呈冶金结合;与Q235钢基体相比,ZrB_2-ZrC/Fe涂层耐磨性显著提高,最高可达基体的5.45倍,ZrB_2-ZrC/Fe涂层的磨损方式以磨粒磨损为主,断裂方式以穿晶断裂为主。

Microstructure and wear resistance of in situ synthesized ZrB2-ZrC/Fe composite coating produced by plasma cladding

A kind of Fe-based ceramic coatings with ZrB2 and ZrC as multi scale strengthening phases on the surface of Q235 steel were fabricated by plasma cladding using Fe,Zr,and B4 C powder mixture as precursor.The phase composition,microstructure,microhardness and the wear resistance comparative test of ZrB2-ZrC/Fe coating and Q235 steel were investigated.The microstructure evolution,the formation of the phase and the wear mechanism were discussed.The results show that ZrB2-ZrC/Fe coatings are composed of ZrB2 ,ZrC,α-Fe,Fe3 C and Fe2 B pha-ses.ZrB2 phase presents acicular,clubbed and petal forms.ZrC phase is irregular polygon shape.With the increas-ing of (Zr+B4 C)raw powder,the contents of ZrB2 and ZrC are increasing,the size of ZrB2 and ZrC become large. The plasma clad ZrB2-ZrC/Fe composite coating is closely and metallurgically bonded to the Q235 steel substrate. Compared with Q235 steel substrate,the wear resistance of the coating is improved significantly,up to 5.45 times than that of the substrate.The main wear mechanism of ZrB2-ZrC/Fe composite coating is abrasive wear,the main fracture mode of the composite coating is transgranular fracture.