Xu Dongyu

Dielectric and Piezoelectric Properties of 2-2 Cement Based Piezoelectric Composite

Cement-based piezoelectric composites with 2—2 connectivity were fabricated from lead magnesium niobate—lead zirconate—lead titanate (PMN) and sulfoaluminate cement by a dice-and-fill technique. The influences of PMN volume fraction and frequency on the piezoelectric and dielectric properties of the composite were analyzed. The results indicated that with increasing the PMN volume fraction, both the piezoelectric strain factor d33 and the relative dielectric factor εr of the composite increased, while the piezoelectric voltage factor g33 decreased. The dielectric resonance peaks, antiresonance absorption peaks, and the dielectric loss peaks of the composites commonly appeared around 200 kHz. With increasing the PMN volume fraction, both the dielectric resonance peaks value and the antiresonance absorption peaks value increased, while the dielectric loss peaks value decreased. At the high frequency zone, the relative dielectric factor εr and dielectric loss tan δ of the composite changed smoothly with increasing frequency.Cement-based piezoelectric composites with 2—2 connectivity were fabricated from lead magnesium niobate—lead zirconate—lead titanate (PMN) and sulfoaluminate cement by a dice-and-fill technique. The influences of PMN volume fraction and frequency on the piezoelectric and dielectric properties of the composite were analyzed. The results indicated that with increasing the PMN volume fraction, both the piezoelectric strain factor d33 and the relative dielectric factor er of the composite increased, while the piezoelectric voltage factor g33 decreased. The dielectric resonance peaks, antiresonance absorption peaks, and the dielectric loss peaks of the composites commonly appeared around 200 kHz. With increasing the PMN volume fraction, both the dielectric resonance peaks value and the antiresonance absorption peaks value increased, while the dielectric loss peaks value decreased. At the high frequency zone, the relative dielectric factor er and dielectric loss tan δ of the composite changed smoothly with incr...

Dielectric, piezoelectric and damping properties of novel 2-2 piezoelectric composites

Here, a strip-shaped 2-2 cement/polymer-based piezoelectric composite was designed and fabricated. The dielectric, piezoelectric and electromechanical coupling properties of the composite were investigated as well as the coupling effects between the thickness and lateral modes of the piezoelectric composites. The dielectric and piezoelectric properties of the composites can be greatly influenced by variations of the piezoelectric ceramic volume fraction and the structural dimensions of the composites. Excellent properties have been achieved for ultrasonic transducer applications in civil engineering monitoring fields, such as large piezoelectric voltage constants, high thickness electromechanical coupling coefficients and low acoustic impedance. The damping property of the composites was especially studied. The maximum damping loss factor of the composites is between 0.28–0.32, and the glass transition temperature is between 55°–66 °C.

Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer.