中国激光, 1996, 23 (3): 265, 网络出版: 2006-12-04
激光熔覆ZrO2/Ni合金复合涂层的凝固组织与分层机制
Solidification Microstructure and Stratification Mechanism of a Laser Clad ZrO2/Ni-alloy Composite Coating
凝固组织 分层机制 复合涂层 激光熔覆 solidification microstructure stratification mechanism composite coating ZrO2 ZrO2 laser cladding
摘要
用激光束在4Cr13钢基体上熔覆ZrO2与Ni合金的混合粉末, 形成了分层结构的复合涂层, 即表面为致密的ZrO2陶瓷层.介于陶瓷层与基体之间的是Ni基合金过渡层。组织分析表明, ZrO2层的上部为等轴晶, 中下部为柱状晶, 主要由t'-ZrO2相及少量沿t'晶界分布的m-ZrO2相组成;Ni合金结合带呈现出树枝晶及其晶间共晶的单一凝固组织。该复合涂层的分层机制可解释为互不混溶的ZrO2与Ni合金熔珠在界面张力和浮力作用下发生离析重排, 再各自重新凝固。
Abstract
Using a laser to clad a mixture POwder of 60 V. -% ZrO2 plus 40 V.-% Nialloy preplaced on steel 4Cr13 substrate, a comPOSite coating that consists of a pure Zro2layer at the upper region and a Ni-alloy bonding zone adjacent to the substrate is formed. The microstructural analyses reveal that the ZrO2layer exhibits equiaxed grains at the upper part and a columnar structure at the lower part and is comPOsed of t-ZrO2 Phase and 2. 9% m-ZrO2 phase distributed along the t boundary. The bonding zone presents an even solidification microstructure composed of Ni-based dendrites and interdendritic eutectics. The stratification mechanism of the composite coating is interpreted as that the insoluble melts of ZrO2 and Ni-alloy powders undergo a redistribution before solidification due to density difference and interfacial tension between these two liquid phases, and then resolidify separately.
裴宇韬, 李冬琪, 雷廷权, 欧阳家虎. 激光熔覆ZrO2/Ni合金复合涂层的凝固组织与分层机制[J]. 中国激光, 1996, 23(3): 265. 裴宇韬, 李冬琪, 雷廷权, 欧阳家虎. Solidification Microstructure and Stratification Mechanism of a Laser Clad ZrO2/Ni-alloy Composite Coating[J]. Chinese Journal of Lasers, 1996, 23(3): 265.