Effect of NaF and CaO/SiO₂ on the Hydrogen Dissolution in the CaO–SiO₂–FeO_t Based Flux System

摘要

The compositional effect of NaF and CaO/SiO_(2) on the hydrogen solubility in the NaF–CaO–SiO_(2)–FeO_(t) welding flux system at 1823 K is presented. At a CaO/SiO_(2) of 1.3, higher NaF decreased the hydrogen solubility and at a CaO/SiO_(2) of 1.5, higher NaF had relatively little effect on the hydrogen solubility in the flux. The hydrogen solubility with CaO/SiO_(2) showed a parabolic behavior showing a minimum near unit basicity and increasing with higher basicity. FTIR (Fourier transform infra red) and Raman spectroscopy of as-quenched flux samples showed the addition of NaF and higher CaO/SiO_(2) depolymerized the flux structure. At low and intermediate basicities from 0.9 to 1.3, higher NaF decreased the incorporated hydroxyl sites of Si(OH) and FeO(OH), which correlates well to lower hydrogen values.