Thermal Property Evaluation of Atmospheric Plasma Sprayed Multilayer Coating of Al2O3 and YSZ

초록

The thermal properties of the multilayer coating consisting of Al2O3 and ZrO2 stabilized by 8% Y2O3 (YSZ) were investigated by plasma spraying. An optical microscope (OM) and a scanning electron microscope (SEM) were used to investigate the shape of the powder and the coating layer, and the phase composition of the powder and the coating layer was determined by X-ray diffraction (XRD). Mechanical properties including surface roughness and porosity were evaluated. Thermal shock and thermal conductivity measurements were performed to evaluate heat resistance. Compared with Al2O3 and YSZ, the multilayer coating has a positive effect on heat resistance at all temperatures. It is believed that this is closely related to the thermal resistance and porosity caused at each coating layer interface. An analysis of steady-state heat transfer has been presented to illustrate the importance of pore, splat interface, and interlayer interface in relation to the overall thermal properties of multilayer coatings.