Study on Structure Characteristics of B2O3 and TiO2-bearing F-Free Mold Flux by Raman Spectroscopy

Structure characteristics of fluoride-Free mold flux containing simultaneously B2O3 and TiO2 have been investigated by Raman spectroscopy in this work. Raman spectra for glass samples with different basicities, different contents of TiO2 and B2O3 were recorded during the experiments. According to the experiments results, increase of TiO2 content leads to the appearance of [TiO4] and [TiO6] structure groups, and [TiO4] becomes the main structure unit in the system. TiO2 produces a certain destructive effect on Si-O-Si network structure as well as large borate group and conducive to the formation of some other complex structure groups, such as (Si,Ti) coupling in sheet unit. It can be concluded that, with the increase of B2O3, the ratio of mixing of the Q(0) structure unit and [TiO4] structural group decrease and the ratio of sheet structure unit increase, and there forms large borate group. Existence of B2O3 increases polymerization degree of the slag system. In addition, increasing basicity causes to the decrease of Q(2) and sheet structure unit and increase of mixing of the Q(0) structure unit and [TiO4] structural group, and weakening the large borate group. It could be concluded that the increase of basicity reduces the degree of polymerization of the system.