Microstructure and thermoluminescent properties of ESAVD produced Eu doped Y₂O₃-ZrO₂ coatings

In this paper the production of smart thermal barrier coatings consisting of yttria partially stabilised zirconia doped with 1 mol.-% of europium is described. These coatings were laid down on Ni based superalloy substrates using a new novel and cost effective coating technique referred to as electrostatic spray assisted vapour deposition. Both a single layered coating and a dual layered coating, consisting of a thin europium doped layer overcoated with a thicker undoped layer, were produced. The thermoluminescent properties of the coatings were investigated and they were shown to be suitable for use as thermographic phosphors enabling temperature measurement at the surface and at the subsurface layer for temperatures of up to at least 1100 K. These results demonstrate the possibility of producing smart thermal barrier coatings with both insulation and instrument properties that would be of great utility in the design and development of cooling systems and protective coatings for components in high temperature regions of gas turbines.