Design and test of a new facility for assessing spectral normal emittance of solid materials at high temperature

Year: 2016

Authors: Mercatelli L., Meucci M., Sani E.

Autors Affiliation: CNR-INO National Institute of Optics, Largo E. Fermi, 6, I-50125 Firenze, Italy

Abstract: The measurement of spectral emittance is a key topic in the study of new compositions, depositions and mechanical machining of materials for solar absorption and for renewable energies. In this work we report on the realization and testing of a new experimental facility for the measurement of directional spectral emittance which provides emittance
spectral information in a controlled environment at medium-high temperatures up to 1300 K. The device is composed by a vacuum chamber with electrical heater optically connected with a visible and an FT-IR spectrometer. A split mirror permits to calibrate the system as it directs toward the detector the signal deriving from a calibrated blackbody. A ZnSe
window allows to measure normal radiance in 0.6-17 μm spectral range. In this device the first test were carried out comparing the results obtained for HfC and TaB2 ultra-refractory ceramic samples to previous monochromatic measurements performed in a research solar furnace, obtaining a good agreement. Then, in order to confirm the reliability of the acquired spectral emittance curve, we compared it to that calculated from the room temperature spectrum in 2.5-17 μm spectral range, showing a similar spectral trend.

Conference title: Optical Components and Materials XIII, SPIE Photonic West 2016

KeyWords: Ceramic materials; Infrared radiation; Solar furnaces; Spectrometers, ceramic; Emittances; High temperature; Solar absorption; Solar plant, Optical properties