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+.