Abstract: A coating for protection of airfoil surfaces from erosion caused by the impingement of particles in the incoming air stream of a gas turbine engine or on helicopter blades. The coating consists of an epoxy film toughened with hard particles to improve the erosion resistance and softer particles which impede the progression of cracks through the coating. A method for applying the coating is also described.

Abstract: Methods for improving the erosion resistance of composite airfoils are disclosed as are the resultant structures. Wire mesh materials are coated with an erosion-resistant coating, formed to the shape of the airfoil leading edge, and molded into the leading edge during airfoil fabrication.

Abstract: A substantially microcrack- and blister-free composite can be made by drying an addition-type polyimide molding compound under suitable conditions to remove excess moisture. The molding compound includes a mixture of a polyimide resin and a plurality of carbon reinforcing fibers less than 3 mm long. The molding compound is placed into a heated material reservoir and transferred to a heated molding tool with a heated transfer ram. The ram establishes a molding pressure in a mold cavity in the molding tool sufficient to cure the molding compound into the desired composite. The molding compound is transferred to the mold cavity such that the molding compound is heated to a molding temperature at a rate of at least about 85.degree. C./min. The molding pressure and temperature are maintained in the mold cavity for a time sufficient to cure the molding compound into the desired composite.