热喷涂NiCoCrAlYTa+7YSZ热障涂层颗粒沉积行为

分别采用低压等离子喷涂和大气等离子喷涂在K4169基体上收集了NiCoCrAlYTa颗粒沉积物及涂层,并对颗粒沉积物的形貌及涂层性能进行了观察分析。结果表明:低压等离子喷涂收集到的单个NiCoCrAlYTa扁平颗粒主要呈圆盘状,涂层致密且氧含量低。而大气等离子喷涂收集到的扁平颗粒主要呈溅射状,涂层孔隙率和氧含量均较高。又在经镜面抛光的NiCoCrAlYTa涂层和K4169基体上分别收集了7YSZ颗粒沉积物,并对其沉积形貌进行了观察分析,结果表明:在K4169基体上收集到的7YSZ颗粒沉积物主要呈圆盘状,表面存在大量的网状微裂纹及宏观环状贯通裂纹。在镜面抛光的NiCoCrAlYTa涂层表面收集的7YSZ颗粒沉积物,周围有少量的指状溅射物,中心部存在一定数量的网状微裂纹,但宏观环状裂纹消失。

Flattening Behavior of Thermally Sprayed NiCoCrAlYTa 7YSZ Particles in Thermal Barrier Coatings

NiCoCrAlYTa splats and coatings were deposited on K4169 substrates by low pressure plasma spray (LPPS) and atmospheric plasma spray (APS), respectively. The microstructures of the splats, and some fundamental properties of the coatings were evaluated in detail. The results show that the splats collected by LPPS performed as disk-shaped ones, while the coating was quite dense with low oxygen content. On the contrary, the splats caught by APS mainly deposited as splash shapes, while the coating has high porosity and oxygen content. 7YSZ splats were deposited on the mirror polished K4169 substrate and low pressure plasma sprayed NiCoCrAlYTa coating respectively, the microstructures of 7YSZ splats were also observed. Typical disk-shaped 7YSZ splat with network of fine cracks and macro circle crack could be found on the K4169 substrate; while the 7YSZ splat deposited on the NiCoCrAlYTa coating has some splash fingers surround the central solidification core, the macro circle cracks almost disappear and less network fine crack could be found, because the intermetallic bond coating can fill the thermal expansion mismatch between substrate and ceramic splat.