Bore Insulator Materials for a Naval Electromagnetic Launcher

Electromagnetic rail launchers are being designed for future long range naval surface fire support. These projectile launchers operate due to the interaction between the magnetic field and current flow between parallel conductive rails. An electric current accelerates a projectile down the barrel at hypersonic velocities. A high strength insulator is required to separate the energized launcher rails and keep them in position while being subjected to the large temperature fluctuations and mechanical forces. Current laboratory EM launcher insulator materials fail due to inadequate toughness, temperature capability, and wear resistance. Not only are materials required that demonstrate the necessary performance in this unique environment, they also must be manufactured in the necessary size for the application. FMI, with support from Lockheed Martin Missiles and Fire Control-Dallas, proposes to develop a new material capable of being produced as large composite bore insulators, with properties sufficient to withstand the electrical, thermal, and mechanical load expected during use. The composite material will utilize a silica pierced fabric preform partially densified via impregnation with colloidal silica, SiO2. After multiple impregnations with the silica, a high temperature polymer (Tg >500 C) will complete the densification and close off any remaining open porosity.