Fundamental Study on Isolation and Determination of Carbides in Steel

Abstract

Some mineral acid separation and potentiostatic electrolysis method for isolation and determination of various carbides in steels have been fundamentally investigated.
The results obtained are summerized as given below.
1. Globular and coarse Fe₃C and other various carbides such as TiC, ZrC, VC, NbC, (Cr, Fe) ₇C₃, (Cr, Fe) ₂₃C₆, Mo₂C and (Fe, W) ₆C were extracted quantitatively by means of potentiostatic electrolysis method with 15% sodium citrate-1.2% KBr-30% citric acid or acethyl aceton-1% tetramethyl ammonium chlolide-methanol electrolyte.
2. The reproducible separation of TiC, VC and NbC with HCl (1+1) and (Cr, Fe) ₇C₃, (Cr, Fe) ₂₃C₆and Mo₂Cwith H₃PO₄ (2+1) could be successfully accomplished if these carbides were relatively coarse.
3.TiC, ZrC and VC being considered insoluble in mineral acids were found to be attacked gradually by diluted HCl, H₂SO₄and H₃PO₃and were mare easily dissolved as the particles cf the carbide were fine.