Casting and Solidification
Effect of Cooling Rate on the Structure of CaO–SiO2–CaF2-based Glassy Mold Flux
2021 年 61 巻 5 号 p. 1532-1538
詳細
2021 年 61 巻 5 号 p. 1532-1538
To evaluate the effect of cooling rate on the structure of CaO–SiO2–CaF2 based mold flux, the structure of glassy mold fluxes prepared at different cooling rates ranging from 20°C/s to 100°C/s were investigated by Raman spectroscopy, 29Si MAS-NMR and XPS techniques. The results shown that the structural species Q2 and Q3 slightly increased with the increase of cooling rate, while the ratio of Q0 slightly decreased. The change of Q1 was negligible. The average number of bridging oxygen atoms increased with the increase of cooling rate. The polymerization degree of the silicate structural network of glassy CaO–SiO2–CaF2-based mold fluxes was found to increase with the increase of cooling rate. The change of the cooling rate obviously caused the structural change of the CaO–SiO2–CaF2 mold flux. The faster the cooling rate, the higher temperature structural feature was founded. The effect of the cooling rate on F-bonds was negligible, and F was found to be mainly in the form of F–Ca bonds.
