Abstract
This study assesses the thermal stability of YSZ coatings produced from nanostructured feedstock by means of atmospheric and suspension plasma spraying. Free-standing YSZ coatings were isothermally treated for 24 h at different temperatures (1200-1600 °C) and at 1550 °C for 20 to 100 h. Afterwards, the coatings were examined to determine the effect of heating on phase composition, microstructure, morphology, and hardness. No evidence of tetragonal-monoclinic phase transformation was detected in the coatings that had been treated for 24 h, even at 1600 °C, but in coatings treated for different periods of time at 1550 °C, a phase transformation occurred after 40 h. Overall, the suspension plasma sprayed coating showed the greatest degree of change due to thermal aging.
