激光重熔镍镀层复合工艺制备铜合金表面涂层

在铜合金表面先预置镍镀层再激光重熔以获得界面冶金结合可靠的新涂层. 通过优化工艺参数，并利用多种分析手段研究了涂层的组织、界面结构和显微硬度. 结果表明，室温下采用4 200 W半导体激光重熔0.4 mm厚镍镀层可获得无缺陷且界面冶金结合可靠的激光熔覆涂层；所获新涂层组织均匀致密，物相由重熔前的γ-Ni镀层转变为重熔后的(Ni，Cu)固溶体；涂层硬度约为135 HV0.05，稍高于CuCrZr基体硬度. 镍镀层的预置和半导体激光的应用提高了铜基表面激光能量的吸收率；新涂层与铜基体间组织成分及硬度匹配保证了良好的界面相容性和可靠的界面结合.

Preparation of surface coating on copper alloy by laser remelting Ni plating coating composite process

Electroplated nickel coating was first deposited on the surface of CuCrZr alloy and then remelted by laser to obtain a new metallurgical coating with reliable interface and metallurgical bond. The microstructure and microhardness of laser remelting coating, and interfacial characteristics were investigated by using X ray diffraction and scanning electronmicroscopy equipped with X-ray energy dispersive microanalysis(EDX), as well as microhardness tester. The results indicated that a laser cladding coating metallurgically combined with copper substrate was obtained after 0.4 mm thick Ni coating was remelted by 4 200 W diode laser at room temperature with scanning speed of 10 mm/s. The absence of defects in the remelting coating with fine and compact structure could be observed. (Ni,Cu) solid solution phase was formed after the Ni plating composed of γ-Ni was remelted. The microhardness uniformly distributed across the section of the coating with the average value of 135 HV0.05, slightly higher than that of the copper substrate(about 125 HV0.05). The matching of the composition and hardness between the new coating and the copper matrix was the basis for ensuring good interfacial solubility and reliable metallurgical bonding.