GB865742A - Improvements in the treatment of refractory metals - Google Patents

Abstract

Niobium and/or tantalum deposited on dissimilar surfaces is reacted with H2 to form a brittle expanded hydride, when the deposits fall away, or may be readily removed, from the surfaces. The metal is heated to 800 DEG -1000 DEG C., either in an H2 atmosphere, or in an inert atmosphere or vacuum with subsequent introduction of H2, and then in both cases is allowed to cool in an H2 atmosphere. The reaction may be under atmospheric or super-atmospheric pressure. The process may be used for removing metal deposited on walls and rods, plates, spheres, or crystals of, e.g. stainless steel or fused silica in the reduction of metal halide, e.g. TaCl5 and NbCl5, with H2 in a heated reactor, e.g. at 800-1000 DEG C. In this application the H2 feed is merely continued during cooling. The hydride may be converted to metal by heating at 800-900 DEG C. while exhausting H2 from the converter, or purging with an inert gas.ALSO:Niobium and/or tantalum deposited on dissimilar surfaces is reacted with H2 to form a brittle expanded hydride, when the deposits fall away, or may be readily removed, from the surfaces. The metal is heated to 800 DEG -1000 DEG C, either in an H2 atmosphere, or in an inert atmosphere or vacuum with subsequent introduction of H2, and then in both cases is allowed to cool in an H2 atmosphere. The reaction may be under atmospheric or superatmospheric pressure. The process may be used for removing metal deposited on walls and rods, plates, spheres, or crystals of e.g. stainless steel or fused silica in the reduction of metal halide, e.g. TaCl5 and NbCl5 with H2 in a heated reactor e.g. at 800-1000 DEG C. In this application the H2 feed is merely continued during cooling. The hydride may be converted to metal by heating at 800-900 DEG C while exhausting H2 from the converter, or purging with an inert gas.