Abstract: A system for the casting of metal comprising a filter through which the metal passes during pouring into a mold cavity. The filter is formed by providing a multiplicity of substantially spherical refractory particles. A ceramic binder is employed for securing the particles in a bonded assembly, the binder substantially completely coating the particles. Openings are defined between the adjoining coated particles to permit the flow of molten metal through the filter. The binder is of a type having an affinity for dross and slag constituents in the molten metal whereby the constituents are removed during passage of the metal through the filter. The refractory particles are preferably bonded into an assembly by processing which includes coating the particles with the binder material, introducing the coated particles into a mold and drying and firing the coated particles in the mold to achieve the desired bonded relationship.

Abstract: This invention is addressed to cores for use in the casting of high melting point metals wherein the core is formed of a refractory material, a silicone resin and a catalyst in the form of an anhydride of an organic carboxylic acid.

Abstract: This invention is addressed to a process for the diffusion coating of metals which are capable of forming a compound or a solid solution with boron by contacting the metal with boron at a temperature greater than 1350.degree.F.