Abstract: An iron-silicon compound powder whose predominant phases are Fe.sub.5 Si.sub.3, Fe.sub.2 Si and Fe.sub.3 Si, which is useful as a radar absorbing material (RAM) in corrosive and oxidizing atmospheres and when used with corrosive or oxidizing binders is formed by a diffusion process. The powder is made in a process that includes blending magnetic materials such as carbonyl iron, iron cobalt, and/or nickel and very pure silicon powders with an activator, such as a halide salt, and then heating the mixture between 1350.degree. F. and 1600.degree. F. in an inert atmosphere. The result is then ground until it passes through a 200 mesh screen. The powder so formed usually is then heated in air. This forms a thin protective shell about each particle of the powder after which the powder can be combined with a suitable binder to form a RAM coating capable of operating at high temperatures which is relatively unaffected by corrosive atmospheres.

Abstract: This application describes a method of rejuvenating reticulated polyurethane materials, particularly those containing ester-type linkages which have been hydrolyzed after being exposed to moisture containing hydrocarbon fuel and/or highly humid environments. The process consists of treating the polyurethane with cross-linking compounds, such as diisocyanates and polyfunctional epoxy compounds.

Abstract: A flame arresting and explosion attenuating system particularly for use in fuel tanks and other similar structures which are designed to contain highly inflammable fluids. The tank or enclosure may be a single compartmented or it may be divided or partitioned into a plurality of individual fuel cells of compartments at least some of which communicate with one another through openings or apertures in the partitions which form them. The subject system is designed to prevent the propagation of flame supported by combustion of the fluid within the tank and to quench the flame when it tries to spread from one compartment to another and to attenuate the explosive forces generated due to ignition of fluid by allowing the forces thereof to be distributed over the total volume of the enclosure so that there is little or no likelihood of the explosion damaging the enclosure.

Abstract: A conduit or other fluid containing structure includes a metal tube having end portions which are exposed for connecting purposes and a liner portion of reduced wall thickness between the end portions. An impregnated braid surrounds the liner portion for rigidifying the same. When the conduit is used as a self-sealing fuel line the thickness of the liner is such that it does not possess enough strength to take on a permanent outward deformation in the presence of the impregnated braid surrounding it, and consequently petalling does not occur. In that application the impregnated braid is surrounded by a sealant capable of swelling when contacted by the fuel, and the sealant is encircled by another impregnated braid to protect and maintain it in place.