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采用激光熔覆技术在45号钢基材上制备出无裂纹Ni60A涂层,详细研究涂层显微组织的凝固特性、相组成及相分布。系统评估涂层和基材在不同载荷下滑动对磨GCr15球时的高温摩擦磨损行为。结果表明:涂层显微组织均匀致密,主要由γ(Ni)固溶体、大量的Ni-Ni3B网状共晶、小花状M23C6及不均匀分布于枝晶间共晶组织中的黑点状CrB组成;涂层显微硬度约为基材显微硬度的2.6倍;相同载荷条件下,涂层摩擦因数大于基材摩擦因数,但摩擦过程稳定;在较高载荷条件下(300 g),涂层磨损率为基材的1/6.2;基材磨损机制为粘着磨损、磨料磨损、严重塑性变形及氧化磨损,而涂层磨损机制则为轻微的磨粒磨损和中等程度的氧化磨损。
The crack-free Ni60A coating was prepared on the steel substrate No.45 by laser cladding. The microstructure and phase composition of the coating were studied in detail. The tribological properties of coatings and substrates were systematically evaluated at high temperature when sliding and grinding GCr15 balls under different loads. The results show that the microstructure of the coating is uniform and compact and mainly consists of γ (Ni) solid solution, a large amount of Ni-Ni3B reticular eutectic, floret M23C6 and black spots CrB in the eutectic microstructure ; The microhardness of the coating is about 2.6 times that of the microhardness of the substrate; under the same load, the friction coefficient of the coating is larger than the friction coefficient of the substrate, but the friction process is stable; under high loading conditions (300 g) The wear rate is 1 / 6.2 of the substrate. The substrate wear mechanism is adhesive wear, abrasive wear, severe plastic deformation and oxidative wear, while the coating wear mechanism is slight abrasive wear and moderate oxidation wear.