超音速激光沉积镀铜CNTs/Cu复合涂层微观结构及耐磨损性能

Microstructure and Wear Resistance of Cu coated-CNTs/Cu Composite Coating Prepared with Supersonic Laser Deposition

采用超音速激光沉积技术(Supersonic laser deposition,SLD)在Cu基体上制备CNTs/Cu复合涂层以提高其耐磨损性能,利用化学镀对CNTs表面进行了表面镀铜处理,在CNTs表面获得了均匀分布的纳米Cu颗粒镀层。对复合涂层的截面形貌、微观结构、磨损性能及机制等进行了分析,结果表明,由于在冷喷涂(CS)过程中同步引入了激光辐照对Cu粘结相进行加热软化,SLD制备的CNTs/Cu复合涂层具有较高的沉积效率和致密性。得益于表面铜镀层的缓冲作用,CNTs在沉积过程中保持了其结构的完整性,在复合涂层中均匀分布且与Cu粘结相结合良好。表面镀铜CNTs的添加使复合涂层具有较低的摩擦因数、磨痕宽度和深度,呈现出较好的耐磨损性能。纯铜涂层的磨损机制为粘着磨损,而CNTs/Cu复合涂层则呈现出粘着磨损与磨粒磨损共存的机制。

Supersonic laser deposition(SLD)is used to prepare CNTs/Cu composite coating on Cu substrate to improve its wear resistance.The surface of CNTs is copper-plated by electroless plating,and a uniformly distributed nano-Cu coating is obtained on the surface of CNTs.The cross-sectional morphology,microstructure,wear performance and mechanism of the as-prepared composite coating were analyzed,and the results showed that due to the simultaneous introduction of laser radiation into cold spray(CS)process to heat and soften Cu powder,CNTs/Cu composite coating prepared by SLD has high deposition efficiency and compactness.Thanks to the buffering effect of the copper coating on the surface,CNTs maintain their structural integrity during deposition process,and are evenly distributed in the composite coating,which are well bonded with Cu powder.The addition of copper-plated CNTs makes the composite coating have a lower coefficient of friction,wear scar width and depth,and show better wear resistance.The wear mechanism of the pure copper coating is adhesive wear,while the CNTs/Cu composite coating shows a coexistence mechanism of adhesive wear and abrasive wear.