Intumescent silicone-based coatings for the fire protection of carbon fiber reinforced composites

The application of carbon fiber reinforced polymer (CFRP) in aircraft structure has introduced potential fire threats and fire protection must be provided. In this paper, intumescent silicone based-coatings (low and high intumescing coatings) are evaluated on CFRP using a bench developed in the laboratory mimicking a jet fuel fire occurring at high heat flux (200 kW/m2). It is shown the development of large intumescence (high intumescing coating) associated with appropriate thermal properties of the coating (heat conductivity measured as low as 0.3 W/m.K) provides efficient protection for the CFRP at the jet fire test. On the other hand, the formation of cohesive ceramic (low intumescing coating) with low heat conductivity (constant heat conductivity as a function of temperature of 0.35 W/m.K) also provides protection but its efficiency is lower than that of intumescent char. It is evidenced that intumescent silicone-based coatings are materials of choice for protecting CFRP in the case of jet fuel fire.