Experimental characterization and physics-based modeling of the temperature-dependent diffuse reflectance of plasma-sprayed NdZrO in the near to short-wave infrared.

Supercontinuum-laser illumination in conjunction with CO-laser heating has been implemented to measure the near to short-wave infrared (970-1660 nm) diffuse reflectance of plasma-sprayed NdZrO as a function of temperature. Owing to the broadband nature of this experimental technique, the diffuse reflectance of plasma-sprayed NdZrO has been measured at many wavelengths and has been shown to decrease with increasing temperature. A physics-based model for diffuse reflectance predicated on the crystal/electronic band structure of highly scattering semiconductor materials has been constructed to interpret the results of these measurements. Baseline materials characterization has also been performed to assist in the development of crystal/electronic band structure-optical property relationships that could be useful for the design of next-generation environmental barrier coatings. This characterization has included ambient and non-ambient x-ray diffraction as well as room-temperature, integrating-sphere diffuse reflectance spectroscopy.