High-Activation Temperature Intumescent Coating for Passive 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 (weight penalty). In this SBIR Phase I project we propose to develop a family of inert, lightweight, high-activation-temperature intumescent coating material to protect military and commercial aircraft engine nacelles and aluminum structures from fire damage. The proposed nanocomposite coating system will expand between 650°F and 1500°F depending on the formulation and will have strong adhesion to the engine and aluminum structures to with stain 5 lbm/sec airflow. Preliminary test results demonstrate that the proposed high-activation-temperature intumescent coating can protect a thin aluminum sheet from fire damage at temperatures up to 950°C. BENEFIT: Commercial applications of the proposed high- activation-temperature intumescent coating include engine nacelles and low-melting point metals like aluminum alloys for airplane, helicopter, vehicles like buses, trains, trucks, automobiles, ships, boats, motorcycles. Additional (secondary) applications may include buildings (historic buildings and residences), bridges, off-shore platforms, wind turbine blades, coated fuel valves in off-shore oil platforms, and caulks to seal cable trays and openings in firewalls. The proposed intumescent coating can be sprayed, brushed, dipped coated, or rolled onto a surface of a component that need fire protection.