铜基材上热障涂层的激光熔敷

Laser cladding of thermal barrier coatings on copper

采用5kW连续CO2激光热源实现了在铜基材上熔敷热障涂层,得到无孔隙、与基体冶金结合的密实ZrO2陶瓷层。发现在ZrO2/NiCoCrAlY界面上生成了Al2O3等氧化物中间层。NiCoCrAlY结合层由胞状晶、胞状枝晶及枝晶组成,其中γ′和β强化相的析出使显微硬度值显著提高。针对TiO2 Al添加剂可以避免裂纹产生,提出陶瓷涂层高温化学反应机制和添加剂中钛在晶界间扩散结合机制。

Zirconia thermal barrier coatings were obtained on copper by a 5 kW CO2 laser, and dense coatings without porosity and with metallurgical bond to substrates were produced. Al2O3 intermediate layer is found at the interface between NiCoCrAlY layer and ZrO2 ceramic layer. NiCoCrAlY bond coatings are composed of cells, cellular dendrites and dendrites, and the precipitation of γ′ and β phases increases the microhardness values. TiO2Al dopants can avoid cracks, so the chemical reaction mechanism in ceramic coatings at elevated temperature, and adhesion mechanism by titanium additive diffusion among the grain boundary were proposed.