Patent ID: 7843114

Claim:
A piezoceramic multilayer actuator comprising: at least two piezoceramic layers comprising a piezoceramic first material sintered at a sintering temperature and having interfacing surfaces along the sides on which the at least two piezoceramic layers are stacked; and a security layer disposed between and extending across substantially the entire interfacing surfaces of the at least two piezoceramic layers; wherein the security layer comprises a matrix of a second material and particles at least partially embedded in the matrix of the second material, wherein the particles comprise a third material different from the first material and different from the second material, and wherein an adhesion between the particles in the security layer and an adjacent piezoceramic layer is weaker than an adhesion between the matrix of the security layer and the adjacent piezoceramic layer, such that a weakened connection between the security layer and the adjacent piezoceramic layer is created.