In Situ High-Temperature Raman Spectroscopy and Simulations for Correlating Structure Evolution with Viscosity in the Binary Potassium Titanate System

The quantitative distribution of various clusters in molten binary K₂O·<i>n</i>TiO₂ (<i>n</i> = 0.5, 1, 2, 3, 4, and 6) was investigated by in situ high-temperature Raman spectroscopy and quantum chemical (QC) <i>ab initio</i> calculation. A series of titanium-oxygen model clusters were constructed, and their symmetric stretching vibrational bands and the corresponding Raman scattering cross-sections of titanium nonbridging oxygen were calculated. The quantitative analysis of various species in molten binary potassium titanate was analyzed by Voigt function deconvolution. The results showed that when <i>n</i> ≥ 4, the structure of melt primarily consists of [TiO₄] and [TiO₅] species, with a small amount of [TiO₆] octahedra. As the K₂O content increases (<i>n</i> < 4), [TiO₄] tetrahedra become the prominent species in the melt. The correlation between viscosity and the distribution of various species at varying temperatures was investigated. The findings indicate that viscosity decreases as temperature and K₂O content increase.