Abstract: This invention involves a method of providing suitable electrical isolation for small metal particles (such as iron) from each other, agglomerating these particles into a larger size, and overcoating the agglomerates to provide environmental protection. A product of this type has attractive electromagnetic absorbing properties at ultra high frequencies even when used in a high temperature environment that would have oxidized uncoated iron particles with resultant deterioration of its absorbing properties.

Abstract: An improved method is provided for converting metallurgical grade silicon to semiconductor grade silicon, by first reacting the impure silicon with silicon tetrahalide to form a mixture of halosilanes, separating and purifying the trihalosilane, and then depositing semiconductor grade silicon by reacting the trihalosilane. The tetrahalide produced as a by-product of the deposition step is recycled to react with additional impure silicon. Improved trihalosilane yields from reacting silicon with the tetrahalide are achieved by adding hydrogen as a reactant, and by immediate quenching of the effluent with HCl. Such improved yields permit the complete system to be internally balanced so that the net production of by-products can be reduced to zero.

Abstract: Composite coatings are formed of a ceramic-type material such as chromium carbide over an intermediate layer of a ductile metal such as nickel on stainless steel turbine compressor blades. Such coatings were found to reduce the erosion by entrained particles to less than 10 percent that experienced by uncoated blades.