Development of a temperature sensitive paint for application in steady and unsteady high temperature environments - Entwicklung einer temperatursensitiven Farbe zur Anwendung in stationären und instationären Hochtemperatur-Umgebungen

Abstract

Temperature sensitive paint is a measurement technique based on photo-luminescence and is usually spray-painted onto surfaces for optical, high resolution spatial temperature measurements. The temperature sensitivity of the paint is limited to a temperature range that differs depending on the paint’s composition. Following extensive research in recent decades at German Airspace Centre in the field of organic sprayable temperature sensitive paints for use at cryogenic and ambient temperatures, the goal for this project is to develop an inorganic sprayable temperature sensitive paint for temperatures ranging from ambient to 500°C that can be applied in tests with high Mach numbers (super-, hypersonic). To achieve this, luminescent powders (LiEuMo2O8, K(Y0.8Eu0.2)(WO4)2, KEu(WO4)2, Y2O2S:Eu, LiEu(WO4)2 and Li3Ba2La(WO4)8) are mixed with liquid binding materials (HPC Binder, Ceramabind 643-1) and spray-painted onto aluminium plates. Intensity and lifetime measurements are acquired at 30°C-230°C and mechanical tests are performed on each coating. For these measurements, existing equipment is modified and a new setup using a heating chamber and a high speed camera is constructed. Based on the results, each mixture is assessed according to preset factors and either modified to achieve optimisation or discarded. Overall, an extensive amount of information and knowledge on paint composition is gained and evaluated.