Abstract: Methods and apparatus are provided for forming a diffusion bonded composite structure. The composite structure includes at least one internal void or feature. Surfaces to be bonded are cleaned and prepared for bonding. The exposed joints of the composite structure where the surfaces interface are sealed. The composite structure is placed in hot isostatic process furnace. The furnace is pressurized to a low pressure below 1500 pounds per square inch that forces the surfaces to be bonded in intimate contact with one another. The composite structure is heated to promote diffusion bonding at the interface of surfaces in contact with one another.

Abstract: A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

Abstract: Apparatus for diffusion bonding, brazing, or joining between respective surfaces of two parts, e.g., the exterior wall of a first annular cylinder and the interior wall of a concentric second annular cylinder, includes a cylindrical body having a circumferential cavity positioned between upper and lower ends thereof. A flexible annular membrane is disposed concentrically over the cavity, and respective upper and lower ends of the membrane are each sealingly hinged to the body. The body is assembled coaxially within the first cylinder, and the assembly then inserted coaxially into the second cylinder to the desired axial bonding position. The cavity is pressurized, causing the membrane, and responsively, the first cylinder, to expand radially within the second cylinder. The temperature of the parts is then raised and maintained for a selected period of time to bond the respective walls of the two cylinders to each other.

Abstract: Methods and apparatus are provided for forming a diffusion bonded composite structure. The composite structure includes at least one internal void or feature. Surfaces to be bonded are cleaned and prepared for bonding. The exposed joints of the composite structure where the surfaces interface are sealed. The composite structure is placed in hot isostatic process furnace. The furnace is pressurized to a low pressure below 1500 pounds per square inch that forces the surfaces to be bonded in intimate contact with one another. The composite structure is heated to promote diffusion bonding at the interface of surfaces in contact with one another.