Effect of SiO₂/Al₂O₃and TiO₂/SiO₂ratios on the viscosity and structure of the TiO₂-MnO-SiO₂-Al₂O₃welding flux system

The effect of SiO₂/Al₂O₃and TiO₂/SiO₂ratios on the viscosity of the TiO₂-MnO-SiO₂-Al₂O₃welding flux system was studied using the rotational spindle method. The viscosity was measured at the fully liquid region of the melt from 1 773 K to the break temperature at approximately 1 623 K. Higher TiO₂/SiO₂ratio resulted in lower viscosity in the temperature range of interest. The SiO₂dominant slag system showed higher viscosity values than the Al2O₃dominant slag in the present TiO₂based system until a SiO₂/Al₂O₃ratio of 1.61. Fourier transform infrared (FTIR) results revealed the [SiO₄]^4--tetrahedral symmetric stretching vibrations and the [AlO₄]^5--tetrahedral asymmetric stretching vibration became weaker with higher TiO₂/ SiO₂, which was also apparent with the increase in the extended basicity ((TiO₂+MnO)/(SiO₂+Al₂O₃)). The Al-O-Si bending vibration and [SiO₄]^4--tetrahedral symmetric stretching vibrations were also pronounced with higher SiO₂/Al₂O₃ratio. From the X-ray photoelectron spectroscopy (XPS) results, the bridged oxygen (O⁰) slightly decreased with higher TiO₂/SiO₂and increased with higher SiO₂/Al₂O₃.