2009 Volume 50 Issue 3 Pages 618-621
Removal of non-metallic impurities like O, N, C and S in 4N Cu rods by argon plasma-arc zone melting and hydrogen plasma-arc zone melting was investigated. The experimental results were discussed on the basis of thermodynamic estimation. Substantial removal of these impurities along the length of the Cu rods by argon plasma-arc zone melting was observed and relatively better removal by hydrogen plasma-arc zone melting was found to be due to activated hydrogen atoms. The removal of O, N, C and S was ascribed to the segregation effect as well as evaporation in the form of CH4, H2O and H2S. As a result, it was found that hydrogen plasma-arc zone melting is a better technique to eliminate non-metallic impurities like O, N, C and S in Cu.