Preparation and characterization of ceramic thin film thermocouples

Indium tin oxide (ITO), alumina doped zinc oxide (ZnO) and NiCrCoAlY/alumina nanocomposites were systematically investigated as thermoelements. These ceramic thermoelements were initially tested relative to a platinum reference electrode and the resulting thermoelectric properties were evaluated. Bi-ceramic junctions comprised of the most stable and responsive ceramic thermoelements, i e those thermoelements with the largest and most stable Seebeck coefficients relative to platinum, were fabricated and tested A bi-ceramic junction based on nitrogen-doped ITO oxygen-doped ITO exhibited excellent high temperature stability and reproducibility, however, this thermocouple pair had a relatively low Seebeck coefficient (6 mu V/degrees C). Alumina doped ZnO ITO thermocouples generated a very large electromotive force at low temperatures but lacked high temperature stability When nitrogen-doped ITO was combined with a NiCoCrAlY/alumina nanocomposite, a very large and stable Seebeck coefficient (375 mu V/degrees C) was realized Ceramic thermocouples based on several candidate materials were demonstrated at temperatures up to 1200 degrees C and the potential of using these materials in other thermoelectric devices including those for energy harvesting is discussed. (C) 2010 Elsevier B.V All rights reserved