Purification of chromium by hydrogen plasma-arc zone melting

Kouji Mimura, Tetsufumi Komukai, Minoru Isshiki

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

Purification of chromium by hydrogen plasma-arc melting (H-PAM) and hydrogen plasma-arc zone melting (H-PZM) has been examined. Especially, reduction of non-metallic impurities, such as oxygen, nitrogen, carbon and sulfur, that have harmful influences on the mechanical properties of chromium, has been investigated. Two kinds of chromium, about 99% (2N-Cr) and 99.99% (4N-Cr) in purity, were used as the starting materials. Remarkable deoxidation, slight denitrogenization and decarburization of chromium were observed in H-PAM, while no reduction of sulfur was observed. Activated hydrogen atoms dissociated in high temperature plasma-arc probably take part in the refining reactions, e.g. deoxidation represented by O + 2H = H20. In addition, it was found that oxygen, nitrogen, carbon and even sulfur concentrations were further reduced at the head side of chromium rods by segregation during H-PZM. Thus, H-PZM with both the segregation effect and the refining effect by H was available to decrease the non-metallic impurities of chromium.

Original languageEnglish
Pages (from-to)11-16
Number of pages6
JournalMaterials Science and Engineering A
Volume403
Issue number1-2
DOIs
Publication statusPublished - 2005 Aug 25

Keywords

  • Chromium
  • Decarburization
  • Denitrogenization
  • Deoxidation
  • Desulfurization
  • Plasma-arc melting
  • Plasma-arc zone melting
  • Purification
  • Segregation

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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