Investigation of Fabrication Condition of Metal Matrix Piezoelectric Composite Using Surface Oxidized Metal Fiber As Internal Electrode

Abstract Piezoelectric ceramics are widely used as sensors and actuators because of their excellent electrical-mechanical energy conversion function. However, the piezoelectric ceramics have the disadvantage of being brittle and not suitable for applications where a large load is applied. To overcome this problem, a metal matrix piezoelectric composite in which piezoelectric ceramics are embedded in a metal matrix with excellent strength has been developed. The developed metal matrix piezoelectric composite is fabricated from a metal-core piezoelectric fiber as the piezoelectric material and aluminum matrix, the metal-core and metal matrix are used as the electrodes. The metal-core piezoelectric fiber/aluminum composite has an output voltage anisotropy with respect to strain, thus, it has unique characteristics as a sensor. Previous studies revealed that this output voltage anisotropy depends on the electrode structure, suggesting that the output voltage characteristics can be adjusted by designing the electrode structure. However, the metal-core piezoelectric fiber is manufactured by extrusion method, and the cross-sectional shape cannot be changed, that is, the output voltage characteristic design is impossible. Therefore, a metal matrix piezoelectric composite that can be designed output voltage characteristics by using surface oxidized metal fibers as internal electrodes has been developed. In this study, the fabrication conditions of this metal matrix piezoelectric composite were investigated. The embedding temperature and pressure were changed, and the structure of the resulting composite was observed and elemental analysis was performed to confirm the presence of chemical reaction between the matrix and the piezoelectric ceramics. As a result, it is found that a range of conditions where the oxide films and the piezoelectric ceramics can be embedded in the matrix without damage.