热喷涂技术沉积环境屏障涂层（EBC）的评估

目前研究的环境屏障涂层用于防护在富含水蒸气的燃烧环境中使用的涡轮发动机部件,为实现本目的需要致密、无裂纹并且具有较好粘结力的涂层。本文对沉积Yb_2Si_2O_7和Si环境屏障涂层的不同热喷涂技术进行了评估。由于快速凝固导致的玻璃化转变以及含硅物质的蒸发,使得耐火硅酸盐材料的等离子喷涂很复杂。硅在喷涂过程中,尤其是在大气环境下,容易被氧化,因此低密度硅的等离子喷涂工艺也需要细致的优化。本文采用了大气等离子喷涂(APS)、超音速火焰喷涂(HVOF)及等离子物理气相沉积(PS-PVD)分别制备了Yb2Si2O7涂层。分析了涂层的微观组织结构、非晶含量以及相组成,针对工艺参数和材料性能,讨论了每种喷涂技术相比于其他喷涂方法的优点和缺点。

As Assessment of Thermal Spray Technologies for Deposition of Environmental Barrier Coatings (EBC)

Environmental Barrier Coatings (EBC) are currently being investigated to protect ceramic matrix composite (CMC) turbine engine components in water-vapor rich combustion environments. Dense, crack-free,uniform and well-adhered coatings are demanded for this purpose. This paper represents an assessment of different thermal spray techniques for deposition of Yb2Si2O7 and (Si) EBC layers. Plasma spraying of refractory silicates is known to be complicated by undesired glass transition due to rapid solidification as well as evaporation of Sibearing species during spraying, particularly at atmospheric conditions. Bearing these problems in mind, the Yb2Si2O7 coatings were deposited by atmospheric plasma spraying (APS), high-velocity oxygen-fuel spraying (HVOF), and plasma-spray physical deposition (PS-PVD) techniques. As-sprayed microstructure, amorphous content and phase composition of the coatings were analyzed. Based on the findings, the advantages and disadvantages of each method over other techniques are discussed with respect to process parameters and material properties.