Geometrical features of plasma-sprayed deposits and their characterization methods

The geometry of Al2O3-TiO2 (13 wt.%) plasma-sprayed deposits produced on flat coupons with various spray gun kinematic parameters was analyzed by several methods: a precise co-ordinates measuring machine (CMM), a laser profilometer, a stylus roughness measuring tester and optical microscopy. A comparative study of these methods was performed. To quantify the deposit geometry a set of parameters was implemented. The deposit morphology was discussed with respect of the deposition timeframe, spray angle and number of passes. At low thickness, the deposit is discontinuous due to the discrete nature of plasma spray deposition, while the profile of thicker deposits is continuous and exhibits a normal distribution. A homothetic growth of deposit with the number of passes was observed. The geometric information was combined to define the geometry of a deposit model to be used for optimization of robotic trajectories in Atmospheric Plasma Spraying (APS).