Abstract: 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⁺.

Key words: manganese doping, PZT, piezoelectric properties