One-step preparation of cast stone from TBFS: Dual effects of TiO2 content on glass network and precipitation behavior

TiO ₂ serves as a nucleating agent with significant impact on crystal precipitation. This study investigates the effects of TiO ₂ content on the properties of CaO-MgO-Al ₂O ₃-SiO ₂ system cast stones and crystal precipitation. Differential scanning calorimetry, x-ray diffraction, scanning electron microscopy, and energy spectrometry were employed to characterize the parent glass and cast stone. The study systematically investigated the influence of TiO ₂ content on the microstructure, crystalline phase, and physical properties of the cast stone. It was discovered that in the absence of TiO ₂, the cast stone primarily precipitated merwinite and melilite crystals. However, the addition of TiO ₂ altered the type and morphology of the precipitated crystal phase. As the TiO ₂ content increased, there was a gradual rise in Tc. Furthermore, while merwinite precipitated in cast stone rapidly decreased, melilite displayed a peaked reduction and augite and Perovskite gradually increased. The addition of TiO ₂ disrupts the original silica-oxygen network, forming two phases with increased crystallinity in subsequent heat treatments, and the formation of titanium-oxygen atomic groups from Ti in the glass network affects the crystalline phase species by influencing the modified cations. The objective of this study is to analyze the role of TiO ₂ in the glass network and its influence on crystal precipitation. The findings provide the necessary theoretical support for crystal precipitation control by regulating TiO ₂ content. The results have significant implications for the development of TBFS-based cast stone materials.