Nano silica modified carbon-phenolic composites for enhanced ablation resistance

High ablation resistant carbon-phenolic (C-Ph) composites were fabricated by the addition of nano silica powder and tested under plasma arc jet at a flux of 2.5 MW m(-2). Nano silica C-Ph composites exhibited much higher ablation resistance compared to conventional C-Ph composites under similar conditions. Microstructure and X-ray diffraction studies reveal that nano silica reacts with char at high-temperature, forming ablation resistant silicon carbide phase. The mechanism of in situ siliconization and the thermophysical properties of the C-Ph composites are discussed. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.