DEVELOPMENT OF INORGANIC FLUORESCENT COATINGS FOR HIGH TEMPERATURE AEROSPACE APPLICATIONS

摘要

For many years, phosphor thermometry has been used for non-contact measurements inhostile high temperature environments, including large blackbody radiation backgrounds,vibration, rotation, fire/flame, pressure, or noise. Often these environments restrict the use ofmore common thermocouples or infrared thermometric techniques. In particular, temperaturemeasurements inside jet turbines, rocket engines, or similar devices are especially amenable tofluorescence techniques. Often the fluorescent materials are used as powders, either suspendedin binders and applied like paint or applied as high temperature sprays. These coatings willquickly assume the same temperature as the surface to which they are applied. The temperaturedependence of fluorescent materials is a function of the base matrix atoms and a small quantityof added activator or “dopant” ions. Often for high temperature applications, the selectedmaterials are refractory and include rare earth ions. Phosphors like Y3Al5O12 (YAG) doped withEu, Dy, or Tm, Y2O3 doped with Eu, or similar rare earth compounds, will survive hightemperatures and can be configured to emit light that changes rapidly in lifetime and intensity.For example, fluorescence from YAG:Dy was recently observed at 1,600 oC at the Oak RidgeNational Laboratory (ORNL) National Transportation Research Center (NTRC) in Tennessee.This paper will give research results applicable to the use of phosphors for thermometrypurposes.