以溶凝膠法與熔淬法製備菫青石玻璃陶瓷之結晶動力學研究

Abstract

本研究利用溶凝膠法(Sol-Gel)與熔淬法(Melt-Quench)製備菫青石玻璃陶瓷(2MgO－2Al2O3－5SiO2)。並利用TGA、DTA、XRD、FT-IR、STEM/EDS來探討結晶現象。為了探討成核劑對結晶的影響，分別添加2 wt% TiO2或2 wt% ZrO2於菫青石玻璃陶瓷中。結果顯示ZrO2與TiO2的添加皆有助於降低結晶活化能；另外玻璃粉末結晶活化能低於凝膠粉末結晶活化能的原因是玻璃粉末在熱處理過程中會有液相而產生黏性流動(Viscous Flow)，使得孔隙降低導致原子擴散變得容易。對兩種粉末而言，μ-cordierite出現在900℃~1100℃之間，1100℃以上μ-cordierite會相變至α-cordierite。對添加ZrO2的試片而言，從XRD與STEM/EDS皆可發現t-ZrO2的存在。

Cordierite glass-ceramic (2MgO-2Al2O3-5SiO2) was prepared by using Sol-Gel and Melt-Quench method. We discussed the phonamenon of crystallization by using TGA, DTA, XRD, FT-IR, STEM/EDS. In order to understand the influence of nucleating agent for crystallization, we added 2 wt% TiO2 or 2 wt% ZrO2 into cordierite glass-ceramic. We found that the addition of TiO2 and ZrO2 decreased the activation energy .Owing to the viscous flow of glass-powder during heat treament, the activation energy for glass-powder was lower than the one for gel-powder. For both gel and glass-powder, μ-cordierite appeared between 900℃ and 1100℃, and μ-cordierite would transform to α-cordierite above 1100℃. For the sample which ZrO2 was added, there would be t-ZrO2.