This paper investigates the evolution of microstructure of thermal barrier coatings (TBCs) produced by suspension plasma spraying (SPS) through a careful experimental study. Understanding the influence of different suspension characteristics such as type of solvent, solid load content and median particle size on the ensuing TBC microstructure, as well as visualizing the early stages of coating build-up leading to formation of a columnar microstructure or otherwise, was of specific interest. Several SPS TBCs with different suspensions were deposited under identical conditions (same substrate, bond coat and plasma spray parameters). The experimental study clearly revealed the important role of suspension characteristics, namely surface tension, density and viscosity, on the final microstructure, with study of its progressive evolution providing invaluable insights. Variations in suspension properties manifest in the form of differences in droplet momentum and trajectory, which are found to be key determinants governing the resulting microstructure (e.g., lamellar/vertically cracked or columnar).

本文通过仔细的实验​​研究，研究了通过悬浮等离子喷涂（SPS）产生的热障涂层（TBC）的微观结构的演变。理解不同悬浮特性（如溶剂类型，固体负载量和中值粒径）对随后的TBC微观结构的影响，并可视化涂层形成的早期阶段（导致形成柱状微观结构或其他形式）是很重要的。具体兴趣。在相同条件下（相同的基材，粘结层和等离子喷涂参数）沉积了几种具有不同悬浮液的SPS TBC。实验研究清楚地表明了悬浮特性（即表面张力，密度和粘度）对最终微观结构的重要作用，研究其逐步发展提供了宝贵的见解。悬浮液性能的变化表现为液滴动量和轨迹的差异，这是控制所得微观结构（例如层状/垂直裂纹或柱状）的关键决定因素。