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基于涂层部分熔化(PM)区比例,孔隙率和结合强度,通过系列实验得到最佳喷涂工艺参数。利用XRD衍射仪,扫描电镜和透射电镜研究等离子喷涂纳米结构Al2O3-13wt%/TiO2(AT13)复合涂层的微观结构;对涂层的显微硬度和断裂韧性进行了Weibull统计,通过磨损实验建立了磨损图。研究表明,涂层存在全熔化(FM)区和PM区,关键等离子喷涂参数(CPSP)的增大促进PM区比例的减小及涂层结合强度的增大。喷涂过程中物相发生了反应,涂层中FM和PM区分别由完全和部分熔化的粒子形成。PM区存在纳米尺寸的晶体和非晶态物质,粒子间发生液相烧结。Weibull统计表明涂层显微硬度和断裂韧性的统计分布存在对应于组织的双态分布。PM区的平均显微硬度低于FM区的,而其显微硬度的分散性更大;PM区的平均断裂韧性及其分散性大于FM区。
Based on the proportion of the partially melted (PM) zone of the coating, the porosity and the bonding strength, the best spray process parameters were obtained through a series of experiments. The microstructure of the plasma-sprayed nanostructured Al2O3-13wt% / TiO2 (AT13) composite coating was studied by XRD, SEM and TEM. Weibull statistics of the microhardness and fracture toughness of the coating were established by wear test The wear map. The results show that the coating has full melting (FM) and PM zones. The increase of the critical plasma spraying parameters (CPSP) promotes the decrease of the ratio of the PM zone and the increase of the bonding strength. The phase reacts during spraying, and the FM and PM zones in the coating are formed of completely and partially melted particles, respectively. There are nano-sized crystals and amorphous materials in the PM region, and liquid-phase sintering occurs between the particles. Weibull statistics show that the statistical distribution of microhardness and fracture toughness of the coating exists in the bimodal distribution corresponding to the microstructure. The average microhardness of the PM zone is lower than that of the FM zone, while the dispersion of the microhardness is greater. The average fracture toughness and dispersibility of the PM zone are larger than that of the FM zone.