Study On Fabrication And Properties Of KNBT Piezoelectric Ceramic Fibers

Piezoelectric fibers not only can be the main phase of the composites to be used as sensors and actuators, but also can be used in micro devices. Their appearances have widely expanded the applications of piezoelectric materials.Na0.5Bi0.5TiO3 (abbreviated as NBT) is a lead-free piezoelectric ceramics with good piezoelectric properties and high electromechanical coupling coefficient, can be a alternative to replay PZT. We use the KNBT ceramic system with a good piezoelectric properties which had studied by our lab, the fibers were fabricated by viscous polymer processing.1-3 piezoelectric composites were prepared by arranging fibers and casting epoxy resin. We discuss the influence of the balling time on the particle distribution and the surface area, analyze the mechanical property of fiber with different particle size, discuss the ferroelectric properties of interdigitated piezoelectric composites with different fiber spacing. Specific work and conclusions are as follows:1,We discuss the influence of the balling time on the particle distribution and the surface area, analyze the mechanical property of fiber with different particle size. As a result, when the milling time extend, the particle size of the powders reduce, the surface area increase, Zeta potential increase. The particle sizes of the powder have high influence to the mechanical property of the fibers. The fibers made by the powder of the average particle size 0.37μm have the highest ultimate tensile strength,40.01MPa.2,Piezoelectric materials with better properties were prepared by VPP for KNBT piezoelectric fibers. The affects of sintering condition on fiber structures and properties were analyzed. And the best sintering condition was done at 1130℃for 2 h. The fiber structure was dense, and the crystal size was uniform. The optimal poling condition was processed on time of 20 min, temperature of 120℃, and electric field of 3.5kV/mm. The piezoelectric strain constant was 69pC.N-1.3,KNBT piezoelectric fibers/epoxy resin composites were made by the arranging-casting technique. The remnant polarization and coercive field of single KNBT fiber in restrained state were 32.5μC/cm2 and 3.8kV/cm, while the remnant polarization and coercive field of KNBT piezoelectric fibers/epoxy resin composites of the fiber volume fractionΦ30% were 6.3μC/cm2 and 3.7kV/cm. The fiber spacing had prodigious effects on the ferroelectric properties. With decreasing the fiber spacing, the remnant polarization increased.