MICROSTRUCTURAL EVIDENCE FOR THE THERMAL-OXIDATION PROTECTION OF CARBON PHENOLIC TOWPREGS AND COMPOSITES/

This study provides microstructural information on changes in the carb on fiber surface as a function of heat-treatment temperature up to 900 degrees C in air, for carbon/phenolic towpregs and composites, respec tively, as made from carbon fiber tow and carbon fabric pre-coated wit h a 0.5 vol.% phosphoric acid solution in methanol. Thermogravimetric analysis and scanning electron microscopy were used. The results show that within the temperature range used in this study, the surface of t he carbon fiber in the towpreg and the composite is protected from pit ting and damage due to thermal oxidation by the coating, and showed a smaller reduction in fiber diameter, compared to the uncoated material . Copyright (C) 1996 Elsevier Science Ltd