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采用超音速火焰喷涂的方法在数控机床主轴表面制备了纳米Ni60-TiB_2复合涂层和常规Ni60-TiB_2微米复合涂层,运用扫描电镜(SEM)、X射线衍射仪等研究了复合涂层的显微形貌、物相组成和耐磨性能,探讨了复合涂层的摩擦磨损机理。结果表明,纳米复合涂层致密、均匀,具有扁平层状分布结构,浅灰色TiB_2颗粒均匀分布在白色Ni-Cr固溶体中;微米复合涂层具有层状喷涂结构,微米级的浅灰色TiB_2相不均匀地分布在白色粘结相Ni-Cr之间,且Ni-Cr固溶体中并没有发现TiB_2颗粒。纳米复合涂层和常规微米复合涂层的物相主要为Ni-Cr固溶体和陶瓷增强相TiB_2,以及次生的TiO_2、NiTi O_3、SiO_2和CrB相;纳米复合涂层的孔隙率小于常规微米复合涂层,而显微硬度、断裂韧性和结合强度均高于常规微米复合涂层;纳米复合涂层的抗滑动摩擦磨损性能优于常规微米复合涂层,纳米复合涂层的主要磨损机制为粘着磨损和磨粒磨损。
The nano-Ni60-TiB_2 composite coating and the conventional Ni60-TiB_2 micro-composite coating were prepared on the surface of the main shaft of the NC machine tool by means of supersonic flame spraying. The microstructure of the composite coating was studied by scanning electron microscopy (SEM) and X-ray diffraction Micro-morphology, phase composition and wear resistance, friction and wear mechanism of the composite coating was discussed. The results show that the nanocomposite coatings are dense and uniform, with a flat layered structure. The light gray TiB 2 particles are uniformly distributed in the white Ni-Cr solid solution. The micrometer composite coatings have a layered spray structure, and the micron-sized light gray TiB 2 phases Uniformly distributed between the white binder phase Ni-Cr, and TiB 2 particles were not found in the Ni-Cr solid solution. The phases of nano-composite coating and conventional micro-composite coating are mainly Ni-Cr solid solution and ceramic reinforced TiB_2, as well as secondary TiO_2, NiTi O_3, SiO_2 and CrB phases. The nano-composite coating has less porosity than conventional micro-composite Coating, while the microhardness, fracture toughness and bonding strength are higher than the conventional micro-composite coating; nano-composite coating anti-sliding friction and wear properties than conventional micro-composite coating, the main wear mechanism of nano-composite coating adhesion Wear and abrasive wear.