Formation mechanism of Al ₂ O ₃ ?YAG amorphous ceramic coating deposited via atmospheric plasma spraying

Al2O3-YAG (Al5Y3O12) amorphous ceramic coatings exhibit excellent crack propagation resistance under harsh wear services due to the phase contributing plastic deformation performance of coating. However, formation mechanism is ambiguous. This study mainly investigated coating prepared by atmospheric plasma spraying from perspective crystallization chemistry. Nano and microsized powders with low eutectic point ratio were selected as feedstock for comparison. X-ray diffraction, scanning electron microscope, backscattered diffraction used analyze composition, morphologies, distribution, structure It concluded that significant thermodynamically stable polycompound high coordination numbers cations prioritized crystallizing in melt, but it needed more time crystallize hardly crystallized limited during spraying. Therefore, selection as-sprayable powder should also be considered critical factor preparing coatings. The nanoscale or submicro scale distributed uniformly was chosen ensure droplets diffuse sufficiently deposition.