Abstract
Changes in phase composition of titania (TiO2) coatings were studied with respect to in-flight particle characteristics during atmospheric plasma spraying. A CCD camera was used to record the average temperature and velocity of TiO2 particles within the plasma jet for six combinations of spraying parameters selected according to Taguchi design of experiments. Phase composition of the coatings was assessed by means of X-ray diffractometry and numerically specified using Rietveld analysis. Changes in composition between the powders and coatings were observed with respect to the in-flight properties of the titania particles during spraying. In general, it was shown that the amount of impurity phases (hematite, quartz) present in the powder decreased after deposition and that in-flight temperature has only a moderate effect on the phase composition of TiO2 coatings. For comparison purposes, additional coatings were deposited by cold spraying and phase composition changes were assessed.