Chemical Science International Journal

This paper presents a comprehensive review of temperature measurement technologies for applications operating above 1000 °C. Accurate temperature measurement in this range is essential for gas turbines, combustion chambers, nuclear reactors, steelmaking, glass processing, and other harsh environmental applications where conventional sensors are limited by oxidation, calibration drift, thermal shock, vibration, signal degradation, and packaging failure. The review covers the principal sensing technologies for extreme-temperature applications, including thin-film thermocouples, optical and fiber-optic sensors, radiation pyrometry, infrared thermography, wireless LC resonant sensors, and surface acoustic wave (SAW) sensors. Special emphasis is placed on thin-film thermocouples because of their direct thermoelectric output, low thermal mass, fast response, and ability to measure surface temperature with minimal disturbance to heat transfer, gas flow, or structural integrity. The review discusses both metallic and ceramic thin-film thermocouple systems and oxide-based sensors, with emphasis on fabrication methods, operating temperature range, response characteristics, stability, and degradation mechanisms. The long-term reliability associated with oxidation, grain growth, interdiffusion, dewetting, agglomeration, pore formation, contact-pad degradation, and thin-film discontinuity was also discussed. This paper also analyzed alternative sensing technologies such as optical pyrometry and infrared thermography. Finally, the paper presents the critical research gaps and roadmap for future research priorities aimed at developing more robust and durable high-temperature sensing systems.