Complex Protective Coatings for Graphite and Carbon-Carbon Composite Materials

The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern the resistance of such protective coatings in air at temperatures up to 2273 K and in the high-speed flows of oxidizing gas media taking place in the spacecraft equipment. Coatings of this type, generally, have a multilayer structure based on the refractory compounds such as carbides, borides, silicides of transition metals and oxides with a high melting temperature. An efficient heat-resistant coating for carbon-based materials should be composed of three layers from which each fulfills its own function. The paper presents a new complex method for formation of heat-resistant coatings on the carbon-based materials. The method combines the vacuum-activated diffusion saturation in the presence of a liquid-phase and self-propagating high-temperature synthesis (SHS) simultaneously.