硬盘基板用微晶玻璃的析晶过程研究

利用差热分析、热膨胀曲线与Ｘ射线衍射等方法研究了含ＴｉＯ_２和ＺｒＯ_２的 ＭｇＯ－Ａｌ_２Ｏ_３－ＳｉＯ_２玻璃的析晶过程．７８０℃时玻璃中析出的镁铝钛酸盐促使玻璃在８００℃析出Ｍｇ－透辉石，随后在 ９３０℃Ｍｇ－透辉石和镁铝钛酸盐开始向假蓝宝石、金红石和Ｚｒ／Ｔｉ固溶体转变；１０３０℃假蓝宝石开始转变为β－石英固溶体，而在１１２５℃以上温度，β－石英固溶体转化为α－堇青石、方石英和顽火辉石，同时金红石和Ｚｒ／Ｔｉ固溶体向锆英石和钛酸镁转变．依据玻璃析晶序列，选择在９３０～１０５０℃间温度下对玻璃进行热处理，制得以假蓝宝石为主晶相的微晶玻璃．此微晶玻璃具有细小均匀的晶粒结构，具有高的弹性模量（１２０ＧＰａ）和良好的表面性能，是适宜的硬盘基板材料．

Crystallization Process of Glass-Ceramic for Substrate of Hard Disks

The crystallization process of MgO-Al₂O₃-SiO₂ glass containing TiO₂ and ZrO₂ was studied by means of DTA, thermal expansion curve and XRD. Magnesium aluminium titanate appearing at 780℃ promotes the crystallization ofMg-petalite at 800℃, and then those crystal phases transform to sapphirine, rutile and Zr/Ti solid solution at 930℃. β-quartz solid solution appears at 1030℃ and transforms at temperature higher than 1125℃ to α-cordierite, cristobalite and enstatite, while rutile and Zr/Ti solid solution transform to zircon and magnesium titanate. According to the crystallization process, a glass-ceramic with sapphirine as the main phase can be prepared at the temperature between 930℃ and 1050℃. The glass-ceramic with a fine-grained structure has large elastic modulus (120GPa) and good surface properties, and is an excellent material for substrate of hard disks.