One-step synthesis of a multi-functional anti-oxidation protective layer on the surface of carbon/carbon composites

A multi-functional anti-oxidation (AO) protective coating is produced in one-step synthesis on the surface of the carbon/carbon (C/C) composite by a novel electrically induced liquid infiltration (EILI) method. The AO coating involves several protective layers which have different anti-oxidation mechanisms. In this study phosphorus acid is applied as active-site poisoning agents to inhibit oxidations by forming stable glassy complex barriers that decrease oxygen diffusion. Simultaneously silicon carbide (SiC) or SiC/silica layers are formed on the surface of C/C composites that act as physical protection barriers for oxygen penetration. It is proved that under the optimum conditions the acid groups survive the high temperature EILI process. Oxidation tests reveal that formed coatings effectively protect C/C composite from oxidation: average percent of weight losses decrease from 30 to 1 wt.% and from 69 to 5 wt.% for the thermal (1150 K) and catalytic (920 K) oxidation tests, respectively.