Development of surface oxidized metal fiber/ piezoelectric ceramics/aluminum composite

Abstract

This paper describes the fabrication of a metal matrix piezoelectric composite using surface-oxidized nickel fiber as the internal electrode. Piezoelectric ceramics, which have excellent piezoelectric properties, are widely used as energy conversion materials. However, their application is limited by their brittleness. To solve this problem, a metal-core piezoelectric ceramic fiber/aluminum composite has been developed by using the interphase forming/bonding method. Here, a piezoelectric ceramic is reinforced by embedding it in an aluminum matrix, and this process causes the piezoelectric ceramic to have better mechanical properties than a bulk ceramic. However, this composite has some serious disadvantages considering that it cannot be designed to possess arbitrary piezoelectric properties because the metal-core piezoelectric fiber is formed by the extrusion method, so that the sectional shape cannot be arbitrarily changed. In this paper, a metal matrix piezoelectric composite using a surface-oxidized nickel fiber as the internal electrode is proposed. This composite provides design flexibility in that its piezoelectric property can be changed by varying the size and materials of the composite. The fabrication procedure of this composite consists of three steps: oxidation of the internal electrode, molding and sintering of the piezoelectric ceramic, and embedding of the piezoelectric ceramic into the metal matrix. The proposed composite is fabricated under optimized oxidizing and molding conditions. An impact test is performed on the fabricated composite, and the output voltage is measured. The test results indicate that the composite is capable of generating piezoelectricity. Overall, the study results substantiate the validity of the concept and fabricating method of the proposed composite.