Effect of FeO t content and CaO/SiO 2 ratio on hydrogen dissolution in CaF 2- CaO - SiO 2-based welding fluxes

Jun Yong Park, Seo Jung Park, Woong Seong Chang, Il Sohn

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The solubility of hydrogen in the CaF 2-CaO-SiO 2-FeO t slag system was studied to characterize the dependence of hydrogen dissolution behavior on the CaO/SiO 2 ratio and the Fe 3+/Fe 2+ redox equilibrium at 1823 K. In an acidic slag composition, the dissolved hydrogen seems to exist as an incorporated hydroxyl, where the supplied water vapor reacts with the bridged oxygen (O o) of the slag network. In a basic slag composition, hydrogen dissolves as a free hydroxyl in the molten slag by reacting with the free oxygen (O 2-). Using FTIR (Fourier transform infrared) and Raman spectroscopy, the addition of FeO t depolymerized the slag structure in an acidic slag system, but polymerized the slag structure in a basic slag system as the FeO t content increased. Furthermore, the formation of γ- and δ-FeO(OH) was controlled by the amount of Fe 2O 3 present in the flux and increased at higher concentrations of Fe 2O 3. At a fixed Fe 2O 3 content and with CaO/SiO 2 ratios varying from 0.7 to 1.3, the hydrogen solubility curve was parabolic as a function of CaO/SiO 2, with a minimum near the CaO/SiO 2 ratio of 1.0 and rapidly increasing at CaO/SiO 2 ratios above 1.0.

Original languageEnglish
Pages (from-to)1756-1763
Number of pages8
JournalJournal of the American Ceramic Society
Volume95
Issue number5
DOIs
Publication statusPublished - 2012 May

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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