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Effect of FeO t Content and CaO / SiO 2 Ratio on Hydrogen Dissolution in CaF 2 – CaO – SiO 2 ‐Based Welding Fluxes
Author(s) -
Park JunYong,
Park SeoJung,
Chang WoongSeong,
Sohn Il
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2012.05173.x
Subject(s) - dissolution , solubility , fourier transform infrared spectroscopy , chemistry , slag (welding) , raman spectroscopy , hydrogen , chemical engineering , inorganic chemistry , analytical chemistry (journal) , materials science , metallurgy , chromatography , organic chemistry , physics , optics , engineering
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 2 O 3 present in the flux and increased at higher concentrations of Fe 2 O 3 . At a fixed Fe 2 O 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.