激光重熔对Cr_3)C_2-NICrBSI等离子喷涂层组织与性能的影响

EFFECTS OF LASER REMELTING ON THE MICROSTRUCTURE AND PROPERTIES OF THE PLASMA SPRAYED Cr_3 C_2-Ni CrBSi COATINGS

为了研究激光重熔对等离子喷涂层组织性能的影响,对Cr_3C_2-NiCrBSi等离子喷涂层进行了激光重熔,且对重熔区进行了显微组织观察,EDM分析以及显微硬度测量,高能量密度的激光束能对Cr_3C_2-NiCrBSi等离子喷涂层进行重熔, 重熔层呈现细小的树枝状铬碳化物组织, 并且具有较高的显微硬度,利用IROS系统、能得到较宽的、熔深一致且稀释较小的高硬度重熔层。在重熔区内能观察到少量空洞及缩孔,为了减少这些缺陷,须认真控制等离子喷涂过程以便于减少气孔及限制元素氧化。

In order to study the effects of laser renelting on the microstructure and properties of the plasma sprayed coating, the Cr3 C2-NiCrBSi plasma sprayed coating was remelted by CO2 laser. Microstructure observation, EDX analysis and microhardness measurement were carried out on the laser remelted region. The Cr3 C2-NiCrBSi plasma sprayed coating can be remelted by high energy density taser beam. The laser remelted layer showed finer dendritic chromium carbide structure and had higher microhardness. In the case of using IROS system, a wider remelted bead with uniform penetration, limited dilution and more higher hardness can be obtained. In the laser remelted bead, some small cavities and shrinkage porosity can be observed. In order to reduce these defects, the plasma spraying process should be carefully controlled to reduce the porosity and to limit the element oxidation.