Multi-layer piezoelectric element and injection apparatus using the same

摘要

A multi-layer piezoelectric element of high durability wherein external electrodes do not peel off the surface of a stack even when operated continuously over a long period of time under a high electric field and a high pressure, a method for manufacturing the same and an injection apparatus using the same are provided. The multi-layer piezoelectric element comprises a stack 10 consisting of a plurality of piezoelectric layers 1 and a plurality of metal layers 2 which are stacked alternately one on another and external electrodes (covering member) 4 that cover at least a part of the side faces of the stack 10, wherein at least one metal layer 2a among the plurality of metal layers 2 is a porous metal layer 2a which has more voids than the metal layers 2b that adjoin the metal layer 2a on both sides thereof in the stacking direction, and a part of the external electrodes 4 infiltrates between two piezoelectric layers 1, 1 which adjoin the porous metal layer 2a in the stacking direction.