Characterization of A12O3, A12O3 + TiO2 Powder Mixture, and Coatings Prepared by Plasma Spraying

Abstract A12O3 and its mixture with 3 wt% Ti02 powders were prepared by fusion and crushing methods. Al2O3 + 13 wt% TiO2 and A12O3 + 40 wt% TiO2 powders were mixtures of fused AI2O3 + 3 wt% TiO2 and 10 wt% and 37 wt% of TiO2respectively. Chemical analysis of the powders showed that: approximately 1 wt% of impurities were present in each powder. True and tap densities were measured and are discussed for all powders. Powder size study showed narrow range of distribution of particle size in each powder. SEM study showed that the particles were in round and other irregular shapes in all the powders. A12O3 was found to be in alpha phase and TiO2 in rutile phase. All the powders were coated by plasma spraying at 16 kW. The density of the coatings were measured and are discussed. In the coatings, A12O3 was in both alpha and gamma phases. In A12O3 + 13 wt% TiO2 and A12O3 + 40 wt% TiO2 coatings, the oxygen reduction from TiO2 was observed.