Qualitative and quantitative evaluation of pre- and post-ablation carbon/carbon composites based on micro-computed tomography

This study qualitatively and quantitatively evaluated the ablation properties of high- and medium-density carbon/carbon (C/C) composites. Ablation tests were conducted at 7.51 MW/m² using an arc-heated wind tunnel. Computed tomography (CT) data were obtained at a resolution of 9 μm using micro-CT. The CT data were then normalized using reference material calibration, and a corresponding relation between the grayscale value and density was established. To verify the accuracy of density and porosity distributions of the test specimens derived from this relationship, masses were calculated and compared to masses measured using an electronic balance. The error rate using micro-CT was low (0.03 %–0.56 %). Microscopic features smaller than 0.05 mm³ (i.e., initial internal defects and defect formation) were analyzed precisely. The study results demonstrate that micro-CT enables nondestructive and highly precise property evaluation and contributes to the development and assessment of thermal protection materials.