海水环境中钛元素改性铜基激光熔覆层的摩擦行为研究

目的通过激光熔覆作用,使钛元素与铜基合金生成耐磨的第二相组织,提升铜基合金表面在海水环境中的耐磨性能。方法采用激光熔覆技术在ZQAl9442镍铝青铜合金表面制备均匀的钛元素改性铜基涂层。采用SEM、EDS、XRD、摩擦磨损试验机等检测仪器,对该改性涂层的显微组织、元素分布、硬度以及在大气与海水环境中的摩擦性能进行分析。结果改性涂层中,因钛元素添加生成了Al Cu2Ti相,使得改性涂层的表面硬度在第二相析出强化的作用下得以提升,显微硬度可达(310±10)HV0.3,相比同质修复层,提升了14.8%。在海水环境中,改性涂层的摩擦系数远低于同质修复层。改性涂层在大气环境中的磨损机制为氧化磨损、粘着磨损及磨粒磨损,在海水环境中的磨损机制为磨粒磨损。结论通过在ZQAl9442铜合金表面进行激光熔覆,得到了兼具高硬度、高耐磨性和抗海水环境摩擦的钛元素改性铜基涂层,在一定程度上提升了镍铝青铜合金在海水环境中的服役寿命。

Tribological Behaviour of Titanium Modified Copper-based Coating by Laser Cladding in Brine

The paper aims to generate a wearable second phase structure by titanium element and copper base alloy to improve the friction performance of copper-based alloy in brine. A titanium modified copper-based coating was fabricated on ZQAl9442 copper alloy via laser cladding. SEM, EDS, XRD and friction and wear tester were used to analyze the microstructure, element distribution, hardness and friction performance of the modified coating. The AlCu2Ti phase was generated due to the addition of titanium element in the modified coating, which improved the surface hardness of the modified coating under the action of the second phase precipitation strengthening. The microhardness of the modified coating was up to (310±10)HV0.3, 14.8% higher than that of the homogeneous repair layer. The friction coefficient of the modified coating in brine was much lower than that of the NAB coating. The wear mechanism of modified coating in atmospheric environment was oxidation wear, adhesive wear and abrasive wear, while the wear mechanism in seawater environment was abrasive wear. Through laser cladding on the surface of ZQAl9442 copper alloy, the titanium-modified copper-base modified coating with high hardness, high wear resistance and resistance to marine environment friction was obtained, which can improve the service life of copper alloy in marine environment to some extent.