悬浮液等离子喷涂与常规等离子喷涂纳米结构陶瓷涂层的研究

Research on Nanostructured Ceramic Coatings by Suspension Plasma Spraying and Conventional Plasma Spraying

采用悬浮液等离子喷涂(SPS)和常规等离子喷涂(CPS)2种工艺制备纳米结构ZrO2/Y2O3涂层。利用XRD和SEM分析涂层的物相和微观组织,同时使用韦伯分布函数对涂层的显微硬度进行了统计分析。研究结果表明:在试验条件下,SPS制备的纳米结构ZrO2/Y2O3涂层为粒状结构,涂层致密且没有观察到显微裂纹。单个层片直径在0.3～4μm之间,平均晶粒尺寸51.8nm。CPS制备的纳米结构ZrO2/Y2O3涂层由部分熔化区和全熔区组成,部分熔化区保持纳米结构。2种方法制备的涂层物相均为亚稳四方相。CPS纳米结构涂层的显微硬度韦伯图呈双态分布,其中全熔区显微硬度较高,离散性大,而部分熔化区显微硬度低,离散性较小。SPS涂层显微硬度离散性比CPS全熔区小,表明SPS涂层组织更为均匀。

Nanostructured ZrO2/Y2O3 coatings were obtained by suspension plasma spraying （SPS） and conventional plasma spraying （CPS）. The phase composition and microstructure of the coatings were characterized with XRD and SEM, respectively. Meanwhile, the microhardness of the nanostructured ZrO2/Y2O3 coatings was also statistically analyzed with weibull distribution function. Research results show that SPS layers exhibit a granular structure under the experimental conditions. The coatings are dense and micro-cracks are not observed. Splat size is in the range of 0.3 to 4 μm. Its average grain size is 51.8 nm. The microstructures of coatings by CPS consisted of melted zones and partially melted zones which keep nanostructured. The phases of the coatings produced by both SPS and CPS are metastable tetragonal phase. The microhardness of coatings produced by CPS present bimodal distribution in their weibull plots. The microhardness of fully melted zones is high with large discreteness while the microhardness of partially melted zones is low with small discreteness. The discreteness of the coatings by SPS is lower than that of the coatings by CPS of fully melted zones, proving the microstructures of coatings by SPS are more homogeneous than that of coatings by CPS.