锰掺杂对硬性PZT材料压电性能的影响

研究了锰掺杂对ＰＺＴ材料微结构及压电性能的影响，并用ＥＳＲ确定了锰在ＰＺＴ材料中的价态．结果表明，锰在ＰＺＴ材料中主要以 Ｍｎ^２＋和 Ｍｎ^３＋的方式共存．锰在ＰＺＴ陶瓷材料中的“溶解度”约为１．５ｍｏｌ％．锰含量＜０．５ｍｏｌ％时，Ｍｎ将以Ｍｎ^２＋和Ｍｎ^３＋的方式优先进入晶格 Ｐｂ位，使材料的压电性能提高，表现出施主杂质特性；锰浓度处于 ０．５～１．５ ｍｏｌ％时，部分Ｍｎ将以Ｍｎ^３＋或Ｍｎ^２＋的方式进入晶格中（Ｚｒ；Ｔｉ）位，而此浓度范围内锰掺杂的ＰＺＴ材料同时表现出“软性”和“硬性”材料的压电特性．锰含量＞１．５ｍｏｌ％时，过量的Ｍｎ将在晶界积聚，使压电活性降低．少量Ｆｅ的存在，可使Ｍｎ离子的溶解度降低，并起到抑制Ｍｎ^２＋和 Ｍｎ^３＋氧化的作用.

Effects of Manganese Addition on Piezoelectric Properties of" Hard ",Lead Zirconate Titanate

The effects of manganese addition on the microstructure and piezoelectric properties of PZT were studied. The valence states of manganese were also measured by ESR. It shows that manganese coexists mainly in Mn2 and Mn3 in PZT ceramics. The solubility limit of MnO in PZT ceramics is about 1.5mol%. Mn ion is preferentially incorporated in the lattice Pb site in Mn2 or Mn3 acted as donor when the concentration of Mn ion is below 0.5mol%, which will improve the piezoelectric properties. In the concentration region of 0.5-1.5mol%, some Mn ion will be incorporated in the lattice of (Ti , Zr) site in Mn3 or Mn 2 acted as acceptor, and correspondingly the Mn-doped PZT ceramics exhibit properties of both "soft" and "hard " piezoelectrics simultaneously. When the concentration of Mn ion is larger than 1.5mol%, it will accumulate at the grain boundaries and give rise to the decrease of piezoelectric properties of PZT ceramics. Small amount of Fe may decrease the solubility limit of Mn ion in PZT ceramics and it may also prevent the oxidation of Mn2 and Mn3 .