Study on aluminium oxide doping modification of indium oxide and thermoelectric properties

Traditional thermocouples face challenges in meeting the temperature measurement requirements of crucial aero-engine components, such as low interference, high temperature resistance, quick response, and in-situ measurement. The temperature measurement requirements mentioned above can be satisfied by thin film thermocouples, thanks to advancements in thin-film preparation technology. In this study, the indium oxide (In₂O₃) was calculated using first principle calculation both before and after doping. It was found that doping Aluminium oxide (Al₂O₃) can increase the Seebeck coefficient of In₂O₃. Solid-phase sintering was used to create aluminum oxide-doped In₂O₃ nanopowders, and thin film thermocouples were fabricated using screen printing. The thermoelectric characteristics of thin film thermocouples were studied to analyze the effects of different annealing procedures and doping concentrations. The optimal annealing process was determined to be at 1300 °C for 1 h, and the ideal doping ratio was found to be Al_0.1In₂O_3.15. The indium oxide film doped with aluminum oxide exhibits a Seebeck coefficient that is 45.9% higher than that of the undoped indium oxide film. The thin film thermocouples underwent tests for impact and vibration resistance, laser pulse response, surface and cross-section morphology, X-ray diffraction, and thermoelectric output. It has been confirmed that doping indium oxide with aluminum oxide can increase a material's Seebeck coefficient. Additionally, a thin-film temperature sensor that has been prepared can be used in challenging conditions to meet the temperature measurement requirements of an aero engine.