Abstract
The effect of the chamber pressure and the spray distance on the splat formation of the plasma sprayed spherical alumina powder was investigated. The velocity and the surface temperature of the sprayed particles were measured by DPV2000. The particle temperature was changed in wide range by the chamber pressure; a solid core remained in the sprayed particle at 30 kPa and the surface temperature reached to the boiling point of alumina over 90 kPa. At the higher temperature, the splashing behavior was explained by the model of liquid film stability. However, in the cooling stage after coming out from the plasma flame, the inhomogeneous temperature in the sprayed alumina particle led to the complex splashing. The temperature distribution in the molten particle is very important to consider the splat formation.
