K-Type Thin Film Thermocouples Deposited on Ni-Based Superalloy Substrates
NiCr-NiSi K-type thin film thermocouples with multi-layer structure were fabricated on Ni-based superalloy substrates (95 mm×35 mm×2 mm). The multi-layer structure contains NiCrAlY buffer layer (2 μm)/ thermally grown Al2O3 bond coating (200 nm)/ Al2O3 insulating layer (8 μm)/ NiCr-NiSi thin film thermocouples (1 μm)/ Al2O3 protecting layer (500 nm). The samples were statically calibrated in a tube furnace in the temperature range from 170 °C to 610 °C. The results show that the resistance of Al2O3 insulating layer is about 14.6 kΩ at 800 °C and exceeds 100 MΩ at room temperature. The Seebeck coefficient a of the samples is about 34 μV/°C, and the sensitivity coefficient K is greater than 0.8 in the temperature range from 170 °C to 610 °C. The maximal sensitivity coefficient is about 0.97 at 265 °C.
Chengming Li, Chengbao Jiang, Zhiyong Zhong and Yichun Zhou
Y. Z. Chen et al., "K-Type Thin Film Thermocouples Deposited on Ni-Based Superalloy Substrates", Materials Science Forum, Vol. 687, pp. 684-687, 2011