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: A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

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.