Effect of NaF and CaO/SiO_2 on the Hydrogen Dissolution in the CaO-SiO_2-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 1 823 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.