激光辅助低压冷喷涂Cu涂层微观结构及导热性能

Microstructure and thermal conductivity of laser-assisted low-pressure cold sprayed Cu coating

针对Cu材料修复需求,采用激光辅助低压冷喷涂技术(Low pressure cold spray,LPCS)在铜基体表面制备Cu涂层,研究了不同激光辐照功率对LPCS-Cu涂层微观结构及性能的影响。结果表明:LPCS-Cu涂层的孔隙率为1.23%,平均显微硬度为124.0 HV_(0.2),热导率为66.2 W/(m·K),涂层/基体界面结合处存在明显缝隙。随着激光辐照功率的增大,LPCS-Cu涂层的表面趋于平整,孔隙率最低可达0.3%,平均显微硬度可达143.4 HV_(0.2),热导率可达170.2 W/(m·K),且涂层与基体界面结合良好,无明显缝隙。这是由于激光辐照提高了沉积颗粒和基体的塑性变形能力,促进了沉积颗粒之间以及沉积颗粒与基体之间的相互结合,使涂层具有较好的致密性和界面结合,表现出较优的导热性能。

In order to meet the repair needs of Cu-based materials,laser-assisted low pressure cold spray(LPCS)technology was used to prepare Cu coatings on the surface of a copper substrate in this study.The effects of different laser irradiation powers on the microstructure and performance of LPCS-Cu coatings were systematically investigated.The results show that the porosity,average micro-hardness and thermal conductivity of the LPCS-Cu coating are 1.23%,124.0 HV_(0.2)and 66.2 W/(m·K),respectively.There are obvious gaps at the coating/substrate interface of the LPCS-Cu coating.As laser irradiation power increased,the surface fluctuation of LPCS-Cu coatings decrease.The porosity,average micro-hardness and thermal conductivity of the LPCS-Cu coating can be optimized to 0.3%,143.4 HV_(0.2)and 170.2 W/(m·K)respectively by the assistance of laser irradiation.The interface between coating and substrate is well bonded without obvious gaps for the laser-assisted LPCS-Cu coating.Laser irradiation improves the plastic deformation ability of the deposited particles and the substrate,which is beneficial to the interfacial bonding between the deposited particles and between the deposited particles and the substrate.Therefore,the laser-assisted LPCS-Cu coating has better compactness and exhibits improved thermal conductivity performance with comparison to the counterpart without laser irradiation.