等离子喷涂纳米结构AT13基涂层硬度的双态分布

Bi-Modal Distribution of Microhardness in Nanostructured AT13-Based Coatings by Plasma Spraying

利用等离子喷涂技术制备纳米结构AT13基陶瓷涂层,通过SEM观察涂层组织结构并利用HXD-1000显微硬度计测量涂层的Vickers硬度,所得结果与对应成分的常规AT13涂层进行对比,结果表明常规涂层只含有单相层片结构,而纳米结构涂层含有双态分布(完全熔化层片结构和部分熔化颗粒结构),常规涂层的硬度平均值要低于纳米结构涂层,纳米结构涂层中存在依赖于微观结构双态分布的硬度Weibull双态分布,而且完全熔化区的硬度由于组织致密明显高于部分熔化区。采用三因素三水平对等离子喷涂纳米结构涂层工艺进行设计,得到影响涂层硬度的最主要的因素是电压,其次是电流。

Nano-structured AT13-based coatings were prepared by plasma spraying,the microstructure and Vickers microhardness of coatings were evaluated by scanning electronic microscope and HXD -1000 micro- hardness tester separately, which compared with the conventional AT13 coatings. Only the single- phase splat microstructure was found in conventional coatings, in contrast, the nano-structured coatings were composed of a bi-modal microstructure which were described as a fully melted splat structure and a partially melted particulate structure. And the microhardness average value of the conventional coatings was lower than the nanostructured coatings. It was observed that the hardness of the nanostructured coatings present a bi-modal distribution in their Weibull plots, indicating the presence of the bi-modal microstructure, and what＇s more, microhardness of the fully melting zone was higher than the partially melting zone because of its dense structure. The plasma spraying parameters that preparing the nano-structured AT13-based coatings were optimized by orthogonal experiment design with three factors in three levels, and as a result, the uppermost factor that controlling the quality of microhardness is voltage and current is the next.