激光熔覆Ni60A涂层对20CrNiMo合金高温干滑动摩擦磨损性能的影响

Effect of Laser Clad Ni60A Coating on High Temperature Dry Sliding Friction and Wear Characteristics of 20CrNiMo Steel

摘要:

为改善制动盘材料的耐磨性能，选用Ni60A粉末，利用光纤激光器对20CrNiMo铸钢进行激光熔覆处理，研究了涂层的微观组织、成分均匀性、硬度、干滑动磨损性能及其损伤机制。结果表明：涂层主要由γ-Ni、M₂₃C₆、Ni-Cr-Fe、Ni₃B、[Fe, Ni]、FeNi₃、NiC、FeNi等相构成，涂层平均显微硬度HV_0.3为4600 MPa，较基体提高2.63倍。与基体相比，涂层在高载、高温工况下具有更小的平均摩擦系数，耐磨性得到显著提升。当载荷为150 N时，在室温和400 ℃时，耐磨性分别提高15.3和22.0倍。随温度和载荷的增加，涂层的损伤机制由磨粒和粘着磨损向氧化和磨粒磨损转变。

Abstract:

To improve the wear resistance of brake disks, the Ni60A coating was prepared on 20CrNiMo steel using laser cladding by optical fiber-based laser system. The microstructure, composition uniformity, hardness, dry-sliding wear performance, and friction and wear mechanism of the Ni-based alloy coating were investigated. The results show that the coating consists of γ-Ni, M₂₃C₆, Ni-Cr-Fe, Ni₃B, [Fe, Ni], FeNi₃, NiC, FeNi, and other phases. The average microhardness HV_0.3 of Ni-based alloy coating is 4600 MPa, which is 2.63 times higher than that of the 20CrNiMo steel substrate. Compared with the substrate, the coating exhibits lower average friction coefficients under working condition of high load and high temperature, and the wear resistance significantly improves. When the load is 150 N, the wear resistance of the coating increases by 15.3 and 22.0 times at room temperature and 400 °C, respectively. With the increase of temperature and load, the wear mechanism of the coating changes from abrasive and adhesive wear to oxidative and abrasive wear.