柱状晶结构热障涂层的沉积生长和织构研究

摘要

等离子体–物理气相沉积(PS–PVD)技术融合了等离子体喷涂(PS)和电子束–物理气相沉积(EB–PVD)的优点,沉积效率高、成本相对较低和可制备柱状晶结构涂层.因此,PS–PVD在制备先进发动机热障涂层(TBCs)上备受关注.利用PS–PVD工艺制备了多种结构的氧化钇部分稳定氧化锆(YSZ)TBCs,采用场发射扫描电镜(FE–SEM)和电子背散射衍射(EBSD)观察和分析涂层微结构与晶体织构特征.试验表明:制备的YSZ涂层为柱状晶结构,在同一喷涂距离处,沿喷涂斑点中心向外围过渡区域,柱状晶端面由四棱锥结构向菜花状结构转变,单柱状晶具有一定的晶体取向,但不同的柱状晶具有不同的结晶取向,制备态陶瓷层整体未呈现明显的择优取向和应力集中.%As a novel technique, plasma spray–physical vapor deposition (PS–PVD) process combines advantages of high deposition rates and cost-efficiency of plasma spraying and columnar structure of electron beam-physical vapor deposition (EB–PVD), so that PS–PVD has received considerable attention to manufacture thermal barrier coatings (TBCs) for some advanced turbines. In this paper, yttria stabilized zirconia (YSZ) coatings were fabricated by PS–PVD. Field emission scanning electron microscopy (FE–SEM) and electron backscatter diffraction (EBSD) were used to observe and analyze the microstructure and crystallographic feature of the coating. The result shows that the microstructure of as-sprayed YSZ coating is columnar structure crystals. During the process of deposition, at a certain spraying distance, the transition zone from the center to the edge of the spraying spot, the end surface of columns is transformed from a quadrangular pyramid structure to a cauliflower-like structure, and the mono-column exhibits a certain preferred orientation, but other columns have different orientations, and the ceramic does not exhibit a distinct preferred orientation on the whole.