Preparation of Heavily Doped Silver-Lead Titanate Composite Films
高掺银-钛酸铅复相薄膜的制备研究

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.