Lightweight High-Expanding-Temperature Intumescent Coating for Aircraft Engine Nacelle Protection

Many fire accidents in aircraft are related to engine nacelle as the environment involving fuel and high temperature. Once fire occur an engine usually lost its operation capability or even explodes. Preventing, suppressing, and extinguishing engine fires are critical engine design factors. Historically, various Halon extinguisher systems were used. The production of these gasses was ceased as they are detrimental to the environment. Another approach was to use intumescent materials to compartmentalize and contain a fire until the aircraft has opportunity to land. However, currently available intumescent materials began to expand at around 200º F. This temperature is too low for an engine nacelle’s environment. Commercially available intumescent coatings are usually applied with a thickness around 9 mm or higher to provide sufficient protection of a structure from fire damage. These values of thickness and weight are too high for aircraft and aerospace structures applications. In this SBIR Phase I project we propose to develop an inert, lightweight, high-expanding-temperature intumescent coating material to protect military and commercial aircraft engine nacelles from fire damage. The proposed nanocomposite coating system will expand at 700°F or higher and will have strong adhesion to the engine structure to withstain 5 lbms/sec airflow. Preliminary test results demonstrate that the proposed high-expanding-temperature intumescent coating can protect a thin aluminum sheet from fire damage at temperatures up to 950°C.