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利用高频辅助激光熔覆技术在镍基合金上制备Al2O3-13%TiO2(质量分数)陶瓷涂层。采用SEM、XRD和EDS等方法分析陶瓷涂层的微观结构和陶瓷层与粘结层之间的结合界面。结果表明:陶瓷层出现了完全熔化区和液相烧结区双层结构,其中,完全熔化区颗粒充分烧结长大,而液相烧结区则出现了三维网状结构,该三维网状结构由熔化的TiO2相包裹Al2O3颗粒形成。通过激光熔覆作用下的粉末熔化和扁平化行为解释双层结构形成机理。同时,在陶瓷层与粘结层的结合界面上发现具有尖晶石结构的NiAl2O4和针状结构的Cr2O3,证明在激光熔覆过程中发生的化学反应可以有效增加陶瓷层与粘结层的结合强度。
Preparation of Al2O3-13% TiO2 (mass fraction) ceramic coating on Ni - based alloy by high frequency laser cladding. The microstructure of the ceramic coating and the interface between the ceramic layer and the adhesive layer were analyzed by SEM, XRD and EDS. The results show that the ceramic layer has a two-layer structure of the complete melting zone and the liquid-phase sintering zone, in which the particles in the complete melting zone are sufficiently sintered and grown while the three-dimensional network structure appears in the liquid-phase sintering zone. The three- TiO2 phase wraps Al2O3 particles. The formation mechanism of the double-layer structure is explained by the melting and flattening behavior of the powder under laser cladding. At the same time, NiAl2O4 with spinel structure and Cr2O3 with needle structure were found on the bonding interface between the ceramic layer and the adhesive layer, which proves that the chemical reaction occurring during the laser cladding can effectively increase the bonding between the ceramic layer and the adhesive layer strength.