High Temperature Thin-Film Sensor Technologies For Advanced Propulsion Materials

In this paper, development of advanced high temperature sensors designed for SiC-based Ceramic Matrix Composites (CMC) materials for use in hot sections of turbine engines is reported. The sensors were fabricated using proven high-temperature materials that have Coefficient of Thermal Expansion (CTE) that closely match those of the CMC and the Environmental Barrier Coatings (EBC). A critical insulating layer made of a highly dense and nanocrystalline material was deposited as a supporting layer for the thin film sensors to overcome the surface roughness and porosity of the EBC-CMC materials. Preliminary high temperature testing show that the RTD sensors have a negative thermal coefficient of resistance (TCR) and detectable changes in the measured resistance with temperatures up to 1,433°C (2,611°F). In addition, the sensors were found to have substantial difference in their measured resistance after exposure to <1,300°C due to a non-reversible phase change.