激光熔覆氧化物陶瓷涂层的微观组织

Microstructure of the laser-clad oxide ceramic coating

本文以制作Al_2O_3,Co,Ni底釉混合物的涂层为例,研究了激光熔覆氧化物涂层的微观组织特征。熔覆形成的涂层是由接近基材表面的Fe-Si-O薄层、粗大等轴晶粒层和细小枝晶组织层构成。从形核结晶理论出发,基于氧化物材料的较低的导热性能,解释了这种微观组织的形成原因。

The microstructure characteristics of the laser-clad oxide ceramic coating based on the mixture of A12O3 powder and ground enamel frit containing Co and Ni was investigated. The formed coating consists of the Fe-Si-O thin layer clinged to the carbon steel substrate, the large-sized equiaxial grain layer in the middle and the outer small-sized dendrite layer. The formation mechanism of the microstructure is explained by the theory on the nucleation and growth of crystal, and the low thermal conductivity of oxide ceramic was considered the main factor for it.