B_2O_3-TiO_2掺杂堇青石微晶玻璃制备及其晶化行为

按照堇青石化学计量配比,掺杂B2O3-TiO2,采用溶胶-凝胶法配合回流制备了以α-堇青石为主晶相的微晶玻璃.利用差热分析、X射线衍射、扫描电镜等测试手段,对该玻璃样品的晶化过程进行了试验观察,探讨了B2O3-TiO2在堇青石基微晶玻璃晶化过程中的作用.结果表明:样品在从无定形态到堇青石微晶玻璃的转变过程中,过渡相为镁铝尖晶石和β-石英固溶体,该结果说明B2O3起到了抑制μ-堇青石形成的作用.另外,TiO2作为形核剂,通过先在玻璃相中形成富钛小液滴来诱导非均匀成核,从而促进α-堇青石析晶.断面扫描电镜图像显示所得微晶玻璃为整体析晶.

Preparation of B2O3-TiO2 Doped Cordierite Glass-Ceramics and Its Crystallization Behavior

Using B2O3-TiO2 as an additive,cordierite glass-ceramics with stoichiometric composition were prepared by the sol-gel technique.The sample crystallization was characterized by differential thermal analysis,X-ray diffraction and scanning electron microscope.Effect of doping B2O3-TiO2 on crystallization was investigated.It is shown that α-cordierite is obtained from amorphous compound,with metastable phases of Al-Mg spinel and β-quartz solid solution produced,indicating that the B2O3 retards the crystallization of μ-cordierite.The Ti-rich liquid drops inducing non-uniform nucleation are formed in the glass phase by doping TiO2,which promotes the bulk crystallization of α-cordierite.