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采用由喷雾造粒制备的纳米团聚粉末并通过等离子喷涂制备出纳米Al2O3-13wt%TiO2涂层.研究分析了涂层的相组成、显微结构、硬度及断裂韧性,结果发现,该纳米涂层呈现出由两部分不同区域组成的双态分布结构:一部分为完全熔化后凝固形成的层状结构;另一部分则为部分熔化的粒状结构,其内保留来源于喷涂喂料的纳米或亚微米粒子.涂层中与未熔纳米α-Al2O3粒子含量成比例的部分熔化区百分数可以通过调整关键喷涂工艺参数(CPSP)来控制.纳米涂层所具有的这种混合结构特性,可以被其力学性能的双态分布特征所证实.Weibull统计分析表明,涂层的显微硬度和断裂韧性均呈现出双态分布,部分熔化区的显微硬度及其分散性均比完全熔化区低,而其断裂韧性及其分散性则均比完全熔化区高.
The nano-Al2O3 powders prepared by spray granulation and the nano-Al2O3-13wt% TiO2 coatings were prepared by plasma spraying.The phase composition, microstructure, hardness and fracture toughness of the coatings were analyzed.The results show that the nano-coating Showing a two-state distributive structure composed of two distinct regions: one part is a layer structure formed after completely melting and solidifying while the other part is a partially melted granular structure, in which nanometer or sub-micron particles originating from spray coating are retained The percent of the partial melting zone in the coating that is proportional to the content of unmelted nano-α-Al2O3 particles can be controlled by adjusting the key spraying process parameters (CPSP) .The mixed structural properties of the nano-coating can be controlled by its mechanical properties The results of Weibull statistical analysis show that the microhardness and the fracture toughness of the coatings show a bimodal distribution, the microhardness and dispersibility of the partial melting zone are lower than the complete melting zone, and the fracture Toughness and its dispersion are higher than the complete melting zone.