Seymour Katz

High temperature reactions between refractory uranium compounds and metals

Solid-solid reactions of various metals (Al, Cr, Fe, Mo, Nb, Ni, Th, Ti, V, Zr, and 304 stainless steel) with refractory uranium compounds (UC, UC/sub 2/, and UN) were investigated at elevated temperatures. The rates of growth of reaction zones were measured, and the products of reaction of some of the more reactive systems were identified. (auth)

Rare-Earth Manganites: Surface-Segregated Platinum Increases Catalytic Activity

Crushed and etched lanthanum lead manganite (La0.7Pb0.3MnO3) crystals containing as little as 0.005 atomic percent platinum have significantly higher catalytic activity than free platinum crystals. This higher activity is due to an almost 100-fold segregation of platinum on the surface. The surface platinum concentration found, 0.5 atomic percent, is sufficient to account for the enhanced activity provided that the platinum has the same activity as platinum supported on alumina.