Some considerations for a method that simultaneously measures the temperature and emissivity of a metal in a high temperature furnace Rev. Sci. Instrum. 75, 5326 (2004); 10.1063/1.1818994 Development of a fast fiber-optic two-color pyrometer for the temperature measurement of surfaces with varying emissivities Rev. Sci. Instrum. 72, 3366 (2001); Use of a multiwavelength pyrometer in several elevated temperature aerospace applications Rev. Sci. Instrum. 72, 1522 (2001); 10.1063/1.1340558High temperature thermal diffusivity measurement by the periodic cylindrical method: The problem of contact thermocouple thermometry Rev.Advanced ceramic materials are widely being developed and studied for application as thermal barrier coatings in the next generation of gas turbine engines. Knowledge of the spectral radiative properties at high temperatures is important so as to ensure the desired effect as a thermal barrier and for accurate radiation thermometry measurements. A bench top instrument previously introduced in this journal has been utilized to determine the high temperature spectral emittance of these materials from measurements of hemispherical-directional reflection and hemispherical-directional transmission in the infrared range of 500-12 500 wave numbers ͑20-0.8 m͒. However, a temperature limitation of the instrument's flat, near-blackbody source of infrared radiance has been shown to result in spectral dependent measurement error that is unacceptable when the sample of interest is a few hundred degrees or more higher than the source. This article describes an improved flat near-blackbody source that allows operation to higher temperatures. Benefits to the desired measurement of high-temperature spectral radiative properties of ceramic thermal barrier coatings are also presented.

Fourier transform infrared (FT-IR) spectroscopy is proving to be reliable and economical for the quantification of many gas-phase species during testing and development of gas turbine engines in ground-based facilities such as sea-level test cells and altitude test cells. FT-IR measurement applications include engine-generated exhaust gases, facility air provided as input to engines, and ambient air in and around test cells. Potentially, the traditionally used assembly of many gas-specific single gas analyzers will be eliminated. However, the quest for a single instrument capable of complete gas-phase monitoring at turbine engine test cells has previously suffered since the FT-IR method cannot measure infrared-inactive oxygen molecules, a key operational gas to both air-breathing propulsion systems and test cell personnel. To further the quest, the FT-IR sensor used for the measurements presented in this article was modified by integration of a miniature, solid-state electrochemical oxygen sensor. Embedded in the FT-IR unit at a location near the long-effective-optical-path-length gas sampling cell, the amperometric oxygen sensor provides simultaneous, complementary information to the wealth of spectroscopic data provided by the FT-IR method.