Preparation of high purity chromium

The purification of chromium is important in investigations of it true properties. High purity chromium was prepared by overlap floating zone refining in a dry hydrogen atmosphere at about 100 kPa. The purity was estimated from the values of the residual resistivity ratio RRRsub(4.2 K) and activation analyses using neutrons, charged particles and γ rays. The concentrations of residual carbon and oxygen were less than 10 ppm for purified chromium, and the highest value of RRRsub(4.2 K) was 667 which is higher than previously reported values. The rolling reduction of the purified chromium was over 50% at room temperature, showing a relatively good ductility. (Auth.)