Abstract: The piezoelectric ceramics (PNW-PMS-PZT) were prepared by traditional ceramics process. The phase
structure of all ceramics samples was analyzed. Results show that the pure perovskite phase is in all ceramics specimens researched. The effect of the content
of PMS, PNW and Zr/Ti ratio on the region of morphotropic phase boundary for PNW-PMS-PZT piezoelectric ceramics was studied. Results show
that the phase structure of PNW-PMS-PZT piezoelectric ceramics changes from tetragonal to rhombohedral with the increase of the amount of PMS, PNW and the ratio of Zr/Ti
in the system. The composition of PNW-PMS-PZT piezoelectric ceramics near the morphotropic phase boundary obtained is the content of PMS: 5～6mol%; the content of PNW: 2～3mol%; the content of PZT: 91～93mol%; the ratio of Zr/Ti: 50/50. At the
same time, there is high piezoelectricity near the morphotropic phase boundary.

Key words: PNW-PMS-PZT piezoelectric ceramics, morphotropic phase boundary, rhombohe-dral, tetragonal