几种金属基板上冷喷涂铜涂层的试验与模拟

采用自主研制的冷喷涂设备在三种典型基板上进行喷涂试验,相同的工艺参数下,在铜和铝基板上得到良好的铜涂层,而在钢基板上则没有沉积.实验结果表明:涂层与基板界面、涂层内部颗粒界面结合良好,铜涂层组织致密,显微硬度高达150HV0.1;从涂层表面形貌扫描电镜(SEM)照片中可以观察到射流状的金属,说明颗粒发生了巨大变形,经计算知颗粒在碰撞中压缩率达69%;粉末和涂层的X射线衍射(XRD)结果表明铜粉末在冷喷涂过程中没有发生氧化.同时,数值模拟了铜颗粒与三种基板的碰撞过程,讨论了形成有效结合的判断准则,根据该准则,计算出铜颗粒在铜、铝、钢基板上的临界沉积速度分别为600m/s,500m/s,800m/s,从而解释了铜颗粒在三种基板上不同的沉积行为.

Preparation and simulation of cold sprayed copper coatings on metal substrate

Experimental study on preparation of copper coatings on three typical metallic substrate was been carried out on self-made equipment.Under same process conditions, copper coatings on copper and aluminum substrate were successfully produced by cold-gas spraying, however, the coating was not obtained on steel substrate. Microstrueture and phases of the coating was examined by means of SEM and XRD, and hardness of the coatings was tested. The results show that the interface between coatings and substrate, and the interface between particles are well bonded. Average microhardness of the coatings is about 150HV0.1. Jet-like metal is observed on the coatings surface, indicating adiabatic shear instability and severe deformation occurs in particles, and the compression rate of particle reachs 69 % by computation. No oxidation of the copper powder occurs in the process of spraying. The process of copper particles impacting on the substrate was numerically simulated, and the criterion for effective bonding was discussed. The critical deposition velocities of copper on copper, aluminum and steel substrate are 600m/s, 500m/s, and 800m/s, respectively, based on the simulation. This can explain the different deposition behavior of copper particle on three substrate.