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

Measurements of YVO/sub 4/:Eu in the form of a thin film and bonded powder, before 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 powder; there was a 500% increase in loss for the bonded powder. Both thin films and bonded powders showed excellent reproducibility for photoluminescent (PL) decay-time temperature measurement. However, for the thin film, the useful temperature range (660-800 K) and sensitivity (18.4 mK/sup -1/) were much better than the bonded powder (700-800 K and 14.6 mK/sup -1/). Evidence here clearly implies that thin films have much better properties for long lifetime thermographic sensing at high temperatures.