Preparation of SiO_2-TiO_2 Graded Glass by Using High Gravity Field Combined with Sol-Gel Method

摘要

A method to prepare the multi-component oxide glass with graded structure was proposed. This method is based on the facts that colloid particles can sediment during a sol-gel transition process under comparatively low gravity field, and the resultant gel can be converted into glass at lower temperature treatment than a conventional method. The graded structure was formed by centrifuging (l0000g level) the Si and Ti mixed colloids, and immobilized by removal of solvent at 90 deg C. This graded precursor gel was heated to 900 deg C to convert into a glass state. The proper condition to prepare the graded glass was examined especially focusing on the growth time of colloids before the centrifugation. A transparent SiO_2-TiO_2 glass with molecular-scale graded structure was obtained in many trials.