Effect of dopants on the phase stability of zirconia-based plasma sprayed thermal barrier coatings

The influence of stabilizer type on the phase stability of thermal barrier coatings (TBCs) produced by air plasma spraying was explored. Together with the widely used zirconia-stabilized with yttria, other novel compositions, such as dysprosia-stabilized zirconia, yttria–lanthana-stabilized zirconia and ceria-stabilized zirconia were also investigated. The effect of isothermal heat treatment on the phase stability was explored. Results suggest that decomposition of the “non-transformable” tetragonal phase occurs to a greater or lesser extent for all dopants at these temperatures. The effect of Al2O3 and SiO2 content was also explored. The rate of decomposition depends on the dopant kind, amount and on the presence of Al2O3 and SiO2 impurities.