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采用粉末共渗法在镍基高温合金表面获得约为280μm厚的铝硅涂层,以纳米氧化铈含胶浆料作为中间体在铝硅涂层表面形成透光预置层后进行激光熔注试验,获得稀土改性的铝硅涂层。以熔深偏离量和缺陷等级为指标对激光工艺参数进行了优化,并采用OM、SEM、EDS及ToupView软件等对比分析了改性前后铝硅涂层的微观组织。结果表明:本文试验条件下,最优的工艺参数为150 W的激光功率、1000 mm·min~(-1)的扫描速度、20 mm的离焦量。在此参数条件下获得的涂层结构,由改性前的3层转变为两层,即基底上分布着“花朵状”细小组织的改性外层和效果增强的扩散障内层。
The surface of the Ni-based superalloy was powder-infiltrated to obtain an Al-Si coating about 280μm thick. The nanosized cerium oxide-containing paste was used as an intermediate to form a transparent pre-layer on the Al-Si coating surface. Test, access to rare earth modified Al-Si coating. The laser process parameters were optimized by taking the deviations of depth of penetration and defect grades as indices. The microstructures of Al-Si coatings before and after modification were analyzed by OM, SEM, EDS and ToupView software. The experimental results show that the optimum process parameters are laser power of 150 W, scanning speed of 1000 mm · min -1, defocus amount of 20 mm. Under the condition of this parameter, the coating structure was changed from three layers before modification to two layers, that is, the modified outer layer of “flower-like ” fine tissue and the diffusion barrier inner layer with enhanced effect were distributed on the substrate.