Simultaneous Measurement Method of Normal Spectral Emissivity and Optical Constants of Solids at High Temperature in Vacuum

Abstract

For the case of the thermal design of devices at high temperatures, radiative properties are important. The emissivity of materials depends on their surface conditions and temperatures. The goal of this study is to measure the emissivity of various materials with clear surface conditions. A system for simultaneous measurements of the normal spectral emissivity, optical constants, and thickness of materials at high temperatures has been developed. To determine an accurate surface temperature of specimens, a surface temperature measurement method is applied using the Christiansen effect. This article focuses on evaluations of the Christiansen effect under various conditions. Measurement results of the normal spectral emissivity of ZrO2 from 773 K to 973 K are also presented.