Effect of Excessive Nb₂O₅ on the Sintering and Electrical Property of Lead Metaniobate Piezoelectric Ceramics

PbNb 2 O 6 -xmol%Nb 2 O 5 (PNx=0, 5, 10, 15, 20) Piezoelectric ceramics were prepared by solid-state reaction method. The effects of excess Nb 2 O 5 on the sintering and electrical properties of PbNb 2 O 6 ceramics were investigated. The sintering and electrical properties were evidently improved after the addition of Nb 2 O 5 into PN in the condition set for a high T c and high coupling anisotropy. The improvement may originate from NbO 6 octahedral distortion by excess Nb 2 O 5 , which prevents phase transition from rhombohedral to tetragonal during the sintering process. With excess addition of Nb 2 O 5 , the piezoelectric coefficient (d 33 ) and relative density of PN ceramics increased and reached up to 69 pC/N and 93.1%, respectively, at 5mol% addition of Nb 2 O 5 .