The effect of thermal oxidation on polycrystalline graphite studied by X-ray tomography

The effect of thermal oxidation on PGA graphite samples was investigated by X-ray tomography. This technique allowed an investigation of the evolution of microstructure and local density to be carried out as a function of weight loss. The results show a localised oxidation process which progressively reveals the large coke particles with increasing overall weight loss. The local density measurements arising from the tomographs were used to estimate the weight loss distribution. The reliability of the values were checked by independent thermal conductivity measurements and volume weight loss calculations by immersion technique.