The modeling of coating thickness, heat transfer, and fluid flow and its correlation with the thermal barrier coating microstructure for a plasma sprayed gas turbine application

The plasma spray deposition of a zirconia thermal barrier coating (TBC) on a gas turbine component was examined using analytical and experimental tech niques. The coating thickness was simulated by the use of commercial off-li ne software, The impinging jet was modeled by means of a finite difference elliptic code using a simplified turbulence model. Powder particle velocity , temperature history, and trajectory were calculated using a stochastic di screte particle model. The heat transfer and fluid flow model were then use d to calculate transient coating and substrate temperatures using the finit e element method. The predicted thickness, temperature, and velocity of the particles and the coating temperatures were compared with these measuremen ts, and good correlations were obtained. The coating microstructure was eva luated by optical and scanning microscopy techniques. Special attention was paid to the crack structures within the top coating. Finally, the correlat ion between the modeled parameters and the deposit microstructure was studi ed.