高掺银-钛酸铅复相薄膜的制备研究

采用溶胶-凝胶法, 通过在新鲜溶胶和在陈化溶胶中分别高掺银这两种制备工艺过程, 制备了分散均匀的立方相银颗粒-钛酸铅相基质复相薄膜. 利用XRD, SEM, TEM等方法对先驱体溶胶和薄膜的组成与结构进行了测试. 研究表明, 溶胶中Ag的存在形式直接对薄膜的晶相形成过程产生影响. 当银以Ag⁺的形式存在于溶胶中时, 银优先消耗部分铅析出银-铅合金相, 体系含银量较少时形成焦绿石相钛酸铅, 含银量较多时, 形成固溶有银的钙钛矿相钛酸铅; 当银以银团簇的形式存在于溶胶中时, 薄膜中直接形成钙钛矿相钛酸铅晶相.

Preparation of Heavily Doped Silver-Lead Titanate Composite Films

Heavily doped silver-lead titanate composite films were prepared via a sol-gel process with fresh sol and aged sol respectively. The composition and structure of precursor sol and film were investigated by means of XRD, SEM and TEM. The results show that silver exists in the form of Ag+ in fresh sol while it forms hexagonal silver clusters in aged sol. The existence state of silver in the sol directly influences the phase formation process of films. When silver exists as Ag+ in the sol, the transformation of Ag+ to silver crystalline particles consumes a lot of Pb2+ to form silver-lead alloy. In the case that silver is slightly doped, Pb2+ deficient pyrochlore Pb2Ti2O7 phase forms because of Pb2+ consumed to form silver-lead alloy; but in the case that silver is heavily doped, the formation of silver-lead alloy saturates, and surplus Ag+ takes the place of deficient Pb2+ and silver-containing perovskite PbTiO3 phase formed. When silver exists in the form of silver cluster in the sol, the formation of silver crystalline phase does not consume Pb2+, perovskite PbTiO3 phase is directly formed in the films.