Analysis of degradation processes of carbon/carbon composites in a high temperature chemical flame by a spectrovideo camera Original Research Article

The purpose of this study is to develop a measurement technique for in situ monitoring of the degradation processes of thermal-resistance materials, such as C/C (carbon/carbon) composites, in high temperature fields. Spatially, spectrally and temporally resolved images of emission from diatomic molecules were observed in an acetylene–air flame by a spectrovideo camera, assembled by combining a monochromator and a high speed ultraviolet (UV) video camera. In order to calculate flame temperatures around the given test samples, C/C composite disks, emission intensity images of two Cr lines were observed by spraying a Cr 1000 ppm solution. The emission intensity images of OH, CH and C2 bands were measured to investigate the degradation processes from their changes. The test samples employed in this study were graphite, two-dimensionally textile C/C composites and oxidation-resistive C/C composites with double layer coatings of SiC and glass materials. Graphite was tested as a reference raw material of the C/C composites. The result indicated that the time dependencies in the spatial distribution of OH and C2 emissions observed by the spectrovideo camera proved to be an effective measure to monitor the degradation/oxidation processes of the C/C composites in high temperature fields.