Comparison between thin film and bonded powder phosphors for thermographicsensing in gas turbine engines

Measurements of YVO4:Eu in the form of a thin film and bonded powder, befor e and after testing in a Rolls-Royce gas turbine engine, indicate that the durability of the thin film was markedly better than that of the bonded pow der; there was a 500% increase in loss for the bonded powder. Both thin fil ms and bonded powders showed excellent reproducibility for photoluminescent (PL) decay-time temperature measurement. However, for the thin him, the us eful temperature range (660-800K) and sensitivity (18.4 mK(-1)) were much b etter than the bonded powder (700-800K and 14.6 mK(-1)). Evidence here clea rly implies that thin films have much better properties for long lifetime t hermographic sensing at high temperatures.