Relationship between the Interlamellar Bonding and Properties of Plasma-Sprayed Y₂O₃-ZrO₂ Coatings

In this study, yttria-stabilized zirconia (YSZ) coatings were plasma sprayed on heated substrates at temperatures ranging from room temperature to 1100 °C. Lamellar mean bonding ratio was estimated from the ionic conductivity of the coatings and mechanical properties were measured by indentation testing. The bonding ratio, elastic modulus, and fracture toughness of the YSZ coatings were found to increase with substrate surface temperature. The results show that the mechanical properties of plasma sprayed ceramic coatings are determined by interlamellar bonding and that significant improvements can be achieved by controlling coating surface temperature.