激光辅助低压冷喷涂表面金属化CNTs/Cu复合涂层

Surface-Metallized CNTs/Cu Composite Coating Prepared by Laser-Assisted Low-Pressure Cold Spray

采用激光辅助低压冷喷涂技术在Cu基体上制备表面金属化CNTs(Ni-Cu-CNTs)/Cu复合涂层,研究了复合涂层的微观特性以及耐磨损性能。研究结果表明,在激光辐照的作用下,Ni-Cu-CNTs增强相和Cu黏结相由于受热软化均发生了明显的塑性变形,Ni-Cu-CNTs颗粒嵌入到塑性变形的Cu颗粒中形成连续致密且结合良好的复合涂层,复合涂层的厚度可达2609μm,CNTs弥散均匀分布在复合涂层中且保持其结构的完整性。添加Ni-Cu-CNTs的复合涂层表现出优异的耐磨损性能,平均摩擦系数可降低至0.385,体积磨损速率降至1.49×10^(-4)mm^(3)/(N·m)。复合涂层中的Ni-CuCNTs增强相一方面通过承受磨球对涂层表面的载荷力,减少了涂层磨损,另一方面随着磨损过程的进行,Ni-Cu-CNTs从涂层中脱离到涂层表面形成润滑层,降低了涂层的摩擦系数,从而提高复合涂层的耐磨损性能。

In this study,surface-metallized CNT(Ni-Cu-CNT)/Cu composite coatings were deposited on a Cu substrate by using the laser-assisted low-pressure cold spraying technique.The microstructure and wear resistance of the composite coatings were studied.The results show that under laser irradiation,significant plastic deformation occurs in the Ni-Cu-CNT reinforcement phase and Cu bonding owing to thermal softening.Ni-Cu-CNT particles are embedded into the plasticdeformed Cu particles to form a continuous,dense,and well-bonded composite coating.The thickness of the composite coating can reach 2609μm,and the CNTs are uniformly distributed in the composite coating while maintaining its structural integrity.The composite coating with Ni-Cu-CNTs shows excellent wear resistance,the average friction coefficient reduces to 0.385,and the volume wear rate reduces to 1.49×10^(−4)mm^(3)/(N·m).Moreover,the Ni-Cu-CNT reinforcing phase in the composite coating reduces the wear of the coating by bearing the load of the grinding ball on the coating surface.In addition,Ni-Cu-CNTs separate from the coating to form a lubricating layer on the coating surface during the wear process,reducing the friction coefficient of the coating,and,thus,improving the wear resistance of the composite coating.