BAS (BaO-Al_2O_3-SiO_2) Glass via Sol-Gel Route

摘要

Transparent BAS gel glasses with compositions near BaO • Al_2O_3 • 2SiO_2 via a sol-gel route are difficult to get because of the great differences in the hydrolysis rates among Si-ethoxide, Ba-ethoxide and Al-isopropoxide. A clear gel could be successfully synthesized by applying three measures; ① stage-by-stage hydrolysis and suitable water amount, ② forming a double-metal alkoxide by the neutralization reaction between Si-ethoxide and Ba-ethoxide, ③ using a dilute solution. Transparent gel glasses with compositions in the range (wt%) of SiO_2: 34～50, Al_2O_3:10～30 and BaO:24～48 were synthesized in this study. Raman spectrum analysis showed that framework structure in the glasses was above 80% and non-bridging oxygen was below 12%, The transition temperatures of the gel glasses determined by DTA analysis were in the range of 917 °C ～ 951 °C.