Abstract: A hollow metal article can be made by casting a metal article around a ceramic core and leaching the core from inside the article. These steps form a hollow space in the shape of the ceramic core. An x-ray detectable agent that has a higher x-ray density than the ceramic core is introduced into the core. Any core remaining inside the article after the leaching step is detected by making and analyzing an x-ray radiograph of the article.

Abstract: A method of bonding a plurality of articles together with an organic adhesive by using a primer that provides increased crack propogation resistance without the use of organic solvents. The method comprises reacting aluminum, titanium, silicon, iron, or zirconium with HBr or HCI. The reaction product is oxidized with a water soluble oxidizing agent to form a hydrosol. The hydrosol is applied to the surface of a metal article prior to the application of adhesive.

Abstract: A method for producing a supported skeletal catalyst is described. The starting material is an alloy which consists of an aluminum or silicon matrix containing fine particles of an intermetallic compound between the matrix material and a catalytically active metal. Chemical means are used to convert the matrix material to an oxide ceramic while removing the matrix material from the intermetallic particles.

Abstract: Photon absorbing surfaces which are effective over a broad band of photon energies are described. These surfaces consist of a two-phase material with a protruding second phase whose dimensions are on the order of microns. Photons are absorbed by multiple reflections within the region of the protruding phase. The surfaces are produced by directional solidification of eutectic compositions to produce aligned second phase microstructures within a metallic matrix. The matrix material is then selectively removed to expose the second phase material.

Abstract: Supported fibrous skeletal metal catalysts and methods of producing such catalysts are described. The catalysts are produced by directionally solidifying a eutectic composition to produce a microstructure consisting of oriented intermetallic single crystal fibers in a metallic matrix. Selective means are employed to remove a portion of the matrix to expose a portion of the fibers. Leaching means are employed to preferentially remove one of the atomic species from the exposed intermetallic fiber. The exposed leached fibers are porous, have a high surface area and display catalytic activity, depending upon the starting eutectic composition.

Abstract: High surface area skeletal metal catalysts and methods of producing such catalysts are described. The production involves solidification of certain eutectic compositions to produce a microstructure of intermetallic fibers in solid solution matrix. The matrix is preferentially removed to provide loose intermetallic fibers which may then be leached to provide a porous structure. Directional solidification is a preferred step in the production process.