High-temperature, normal spectral emittance of silicon carbide based materials

Abstract

An emissometer was designed and constructed to measure the normal, spectral emittance of opaque solids over the spectral range from 1 to 8 microns for temperatures ranging from 500 to 1500 C using an integral blackbody technique. The emissometer is gas-tight so that the gas environments surrounding the sample can be controlled and emittance data can be collected as a function of exposure time to a specific environment at a particular temperature. An FT-IR spectrometer collects the blackbody and sample IR signals, which are ratioed to calculate the material's emittance. A computer code was developed to check the validity of the assumptions associated with the measurement technique. The emittance of silicon carbide in the form of alpha-SiC and TiB2-toughened SiC was collected over the spectral and temperature ranges given above. The surface morphology and composition of the samples were characterized using SEM, EDX and XRD techniques. 13 refs.