Modeling of Phenomena Occurring in Plasma Jet at Suspension Spraying of Hydroxyapatite Coatings

The phenomena occurring after an injection of water-ethanol suspension of hydroxyapatite are analyzed by a mathematical simulation. Firstly the suspension is submitted to a hydrodynamic breakdown and an intensive evaporation of liquid phase takes place. The evaporation modifies the transport properties of the working gas. Then the small, initially solid hydroxyapatite particles get molten and, eventually, sintered with other small particles to create larger agglomerates. The temperature and velocities of such particles are calculated.

The mathematical modeling includes also the calculation of the map of velocity and temperature of working gas. The mathematical simulation enables to calculate the heat flux arriving to the substrate. This flux is compared to that measured experimentally at suspension plasma spraying of hydroxyapatite coatings.