Hydrogen Dissolution in the TiO₂–SiO₂–FeO and TiO₂–SiO₂–MnO Based Welding-Type Fluxes

摘要

The hydrogen solubility of TiO_(2)–SiO_(2)–FeO and the TiO_(2)–SiO_(2)–MnO welding-type flux systems have been studied to identify and compare the hydrogen dissolution behavior in molten welding fluxes at high temperatures of 1823 K in a wide range of compositions. The dependence of the water vapor pressure and the hydrogen solubility showed a slope of 1/2 suggesting thermodynamic equilibrium was obtained. For an acidic slag composition, the hydrogen was found to be incorporated within the silicate network structure and decreased with higher TiO_(2) additions due to the dilution effect of SiO_(2) and subsequent decrease in incorporation sites. The additions of FeO and MnO, which acts as a basic component to the slag system, provided free oxygen ions, and decreased the incorporation sites for hydrogen dissolution. FTIR analysis of as quenched molten flux samples showed more pronounced bands for Si–OH bending vibrations when hydrogen solubility increased. For a basic slag composition, the hydrogen existed as a free hydroxyl and the addition of basic components such as FeO and MnO to the slag system increased the hydrogen solubility in the molten slag. Furthermore, it was observed that the hydrogen solubility was slightly lower for FeO than MnO containing fluxes.