Recent Developments

Abstract

Zone-refining of metals -- One of the most striking devel-opments of recent years in physical metallurgy is the zone-refining of metals. This technique, introduded by pfann in 1952, has led to remarkable advances in theoretical know-ledge of metals, on the one hand and in the huge trans-istor and semiconductor industry on the other. It has res-ulted in the development of methods for the accurate and reliable estimation of impurities in metals in amounts fantastically low and considered to be quite beyond the reach of the most refined microchemical analytical meth-ods.