Effect of reynolds number of molten particle on splat formation in plasma spraying

Abstract

Effect of Reynolds number on the flattening behavior of in-flight particles was investigated by slit method. Molten 6wt%-8wt% yttria-stabilized zirconia (YSZ) particles with different Reynolds numbers were collected. The morphology of splats was examined using scanning electron microscope (SEM) and 3D laser microscope. Meanwhile, the behavior of spreading, heat transfer and solidification of YSZ droplets with different Reynolds numbers were simulated by CFD software Fluent. The results show that the flattening behavior of molten particles is significantly influenced by Reynolds number when Ohnesorge number exceeds 0.2. The splat tends to splash with the increase of Reynolds number. At a lower Reynolds number, the splats exhibit a regular disc-shape. However, when Reynolds number reaches 450±20, splats begin to splash. In addition, for the original molten particles with the same diameters, the flattening ratio of molten particles in supersonic atmospheric plasma spraying (SAPS) is approximately 1.3 times as much as that in atmospheric plasma spraying (APS).