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 Pb(2+) to form silver-lead alloy. In the case that silver is slightly doped, Pb(2+) deficient pyrochlore Pb(2)Ti(2)O(7) phase forms because of Pb(2+) 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 Pb(2+) and silver-containing perovskite PbTiO(3) phase formed. When silver exists in the form of silver cluster in the sol, t