THERMAL-ANALYSIS OF PLASMA-SPRAYED THERMAL BARRIER COATINGS

A DSC/TGA and XRD study on the thermal stability of yttria-stabilized zirconia TBC (thermal barrier coatings) obtained by atmosphere- and te mperature-controlled plasma spray, was carried out. As-sprayed zirconi ca coatings were under-stoichiometric and highly disordered. The therm al analysis showed that several endo- and exothermic phenomena take pl ace on heating the ceramic. TGA clearly showed weight gains associated with the oxygen recovery, whereas DSC also detected the structural re laxation and transformations found by XRD. The activation energies, re action order and mechanism are also discussed.