Papers by Author: Li Li Guo

Abstract: Sulphoaluminate cement and Lead Niobium-Magnesium Zirconate Titanate ceramic [P(MN)]ZT were used as matrix and functional phase respectively to fabricate 1-3-2 cement-based piezoelectric composites by dice and filling technique. The influences of base thickness on piezoelectric properties, electromechanical properties and acoustic impedance properties of the composites were discussed. The results show that as the base thickness increases, the piezoelectric stain factor d33 increases gradually, while the piezoelectric voltage factor g33 decreases. The planar electromechanical coupling coefficient Kp exhibits the trend of decrease, while the thickness electromechanical coupling coefficient Kt and acoustic impedance show the increasing trend. The mechanical quality factor Qm reaches the minimum (1.49) when base thickness is 2.00 mm. The results reveal that the 1-3-2 piezoelectric composite will be suitable for application by changing the base thickness.

Abstract: Piezoelectric ceramic(lead niobium lithium zirconate titanate, P(LN)ZT), sulphoaluminate cement and polymer were used to fabricate 1-3 polymer/cement based piezoelectric composites by cut-filling technique. The influence of P(LN)ZT aspect ratio on the piezoelectric and dielectric properties of composites was investigated. The results show that as the P(LN)ZT aspect ratio increases, the piezoelectric strain factor d33 and relative dielectric factor εr decrease evidently, while the piezoelectric voltage factor g33 decreases slowly. The acoustic impedance Z is hardly influenced by the aspect ratio. At the same time, the influence of temperature on the dielectric properties of the composites was studied. The results show that with increasing the temperature at the frequency of 1kHz and 150 kHz, the dielectric factor εr exhibits the trend of increase. In the range of -40°C-110°C, the dielectric loss tanδ first increases slowly, but when exceeding the temperature of 80°C, it increases evidently. Comparing with P(LN)ZT piezoelectric ceramic, the vibration at thickness mode of 1-3 type piezoelectric composite is strengthened.

Abstract: 2-2 cement based piezoelectric composite was fabricated using sulphoaluminate cement and lead magnesium niobate-lead zirconate-lead titanate ceramic (P(MN)ZT) by dice-and-fill technique. The effects of composite thickness on dielectric, piezoelectric and electromechanical properties of the composite were analyzed, respectively. The results show that the increase of composite thickness will improve the piezoelectric strain factor d33 of the composite, while decreases the piezoelectric voltage factor g33 of the composite. The relative dielectric factor εr as well as the dielectric loss tan δ of the composite also increases with increasing the thickness. The electromechanical analysis results show that the thickness electromechanical coupling coefficient Kt of the composite increases obviously with decreasing the thickness, meanwhile the mechanical quality factor Qm of the composite shows the increasing trend, thus, the receiving piezoelectric transducers can be fabricated by decreasing the thickness.