钒氮合金对激光熔覆钴基合金涂层组织和耐磨性的影响

利用5 kW CO2连续激光,在低碳钢表面熔覆钴基合金和添加钒氮合金的钴基合金涂层.采用光学显微镜(OP)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射仪(XRD)研究了熔覆层的显微组织和相结构;利用显微硬度计及滑动磨损试验机测试了熔覆层的硬度和抗磨损性能.结果表明,Co基合金涂层主要组成相为γ-Co与碳化物Cr23C6;加入钒氮合金后,出现了σ-FeV和VN等相,涂层凝固组织明显细化,熔覆层硬度提高,凡界面处硬度均比表层高;熔覆层的耐磨性随钒氮合金的加入及激光扫描速度的增加而提高,同时对熔覆层的磨损机制进行了分析.

Effect of V-N Alloy on Microstructure and Wear Resistance of Co-Based Alloy Laser Coating

Co-based alloy coatings with and without V-N alloy addition were cladded on the surface of the low carbon steel (SPHC). The microstructure and phases of the coatings were studied with optical microscope (OP), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction instrument (XRD). The microhardness and sliding wear resistance of the coatings were also tested. The results show that γ-Co and Cr23C6 exists in Co-based alloy coatings. Fine microstructure and other phases, such as σ-FeV and VN are obtained with V-N alloy addition. The microhardness is improved and higher at interface than that near the top surface. With the increase of laser scanning speed, the wear resistance of the coatings is improved by adding V-N alloy. The abrasive mechanism of the coating is also analyzed.