EFFECTIVE SPECTRAL EMISSIVITY MEASUREMENTS OF SUPERALLOYS AND YSZ THERMAL BARRIER COATING AT HIGH-TEMPERATURES USING A 1.6 MU-M SINGLE-WAVELENGTH PYROMETER

A method which employs an integrating sphere and a single-wavelength ( 1.6 mu m) pyrometer for measuring the spectral effective emissivities of superalloys in the temperature range (= 650-1050 degrees C) is desc ribed. The spectral effective emissivities for five superalloys, namel y, MARM-247, MARM-509, CMSX-4, Inconel-718, N-155 and two Rene-N6 samp les coated with YSZ thermal barrier coating were measured. Correcting the pyrometer measurements for the variations in the object emissivity would reduce the uncertainty in the temperature measurements to < +/- 1%. (C) 1998 Elsevier Science Ltd. All rights reserved.