【作者】 全静；

【导师】 龚红宇；

【作者基本信息】 山东大学 ， 材料学， 2010， 硕士

【摘要】 0-3型水泥基压电复合材料不但具有与土木结构中混凝土母体的良好相容性,而且其与混凝土结构材料有优良的阻抗匹配关系,两者间界面粘结效果显著。0-3型水泥基压电复合材料具有易于制备、成本低、性能可靠的优点。其压电性能优越,可制造混凝土结构中的水泥基传感器。本文以PZT压电陶瓷与水泥复合制备得到压电性能较好的水泥基压电复合材料。以不同种类的锆钛酸铅(PZT)压电陶瓷为功能相,分别用普通硅酸盐水泥和白水泥为基体,并添加少量碳黑和碳纳米管,采用压制成型法制备了0-3型水泥基压电复合材料,具体研究内容及结果如下：研究了不同压电陶瓷相(P41,P43,P51和P52),以及不同水泥基体等对水泥基压电复合材料性能的影响因素,并分析了其微观结构。水泥基压电复合材料的压电与介电性能主要受压电陶瓷相的影响,故由P52与P51制成的复合材料的压电应变常数及介电常数高于由P41与P43制成的复合材料。而由P52与P51制成的复合材料的介电损耗与阻抗高于由P41与P43制成的复合材料。复合材料的压电常数均随着压电陶瓷相的增多而增大。三种不同水泥基体制备的水泥基压电复合材料中,压电常数均随着PZT压电陶瓷含量的提高而增大。其中波特兰水泥对压电性能的贡献稍微较大,介电性能三者相差不大。探讨了压电陶瓷粒度对0-3型水泥基压电复合材料压电及介电性能的影响。PZT粉体平均粒度为3μm到482μm。结果表明d33,εr和Kt值均随着PZT粒度的增大而增加。但是含有较大PZT颗粒的复合材料的介电损耗tanδ同样较大。根据XRD等测试结果,较小PZT粒度伴随而来的d33,εr和Kt值的减小可能是PZT颗粒和水泥基体之间的表面多孔造成的。而PZT粒度较小时复合材料的结构较为紧实和致密。用金属醇盐通过溶胶-凝胶法制备出纳米PZT粉体。XRD等分析结果证实了700℃烧结的PZT粉体中仅有烧绿石相存在。700℃烧结的PZT粉体的平均粒度大约为200nm,而计算出晶粒尺寸为26.4nm。纳米PZT粉体和水泥采用压制成型法制得。测试了水泥／纳米PZT压电复合材料的压电性能。和掺加较大粒度的PZT颗粒相比,水泥／纳米PZT压电复合材料呈现出比较优越的压电性能。用白水泥为基体,PZT粉体为功能相,并添加少量的碳黑,来制备0-3型水泥基压电复合材料。研究了碳黑／PZT／水泥复合材料中老化的实质以及其极化行为。结果表明加入碳黑相之后极化过程得以在常温下进行。也研究了碳黑对复合材料压电性能及介电性能的影响。结果表明复合材料的压电性能因为碳黑加入而呈现较大提高,主要原因是碳黑的导电性比较好。在极化电压4kV／mm和极化时间20min的条件下,含70vol.％PZT的压电复合材料d33,εr,tanδ和Kt值分别为：28.5 pC／N,202.6,0.19和12.2％。研究了纳米碳管的分散对PZT／cement压电复合材料的压电性能的影响的研究。0-3型碳管／PZT／cement压电复合材料是由硅酸盐水泥和一定粒度比例的PZT粉末和纳米碳管通过混合制备而成的。本文对含有不同处理方法的碳管、不同分散方法和不同含量碳管的压电复合材料的压电以及介电性能进行了研究。实验结果表明：用Fenton／UV方法处理的纳米碳管的分散性最好,碳纳米管对水泥基压电复合材料的压电性能和介电性能都有显著的改善作用。Fenton/UV法处理CNTs,去除其中的非晶杂质比较彻底。HNO3氧化法和Fenton/UV处理后的CNTs表面存在-C=O、-COOH、-OH等官能团。复合材料的压电应变常数随着CNTs含量的增加而增加,当CNTs的加入量为0.10wt％时,其d33值最大,为54 pC／N。但过量的CNTs会使复合材料的压电性能降低,这是由于过量的CNTs可破坏水泥基体的绝缘性,使复合材料无法极化。更多还原

【Abstract】 0-3 cement-based piezoelectric composites exhibit reasonable piezoelectric activities as well as similar acoustic impedance to concrete stucture. Besides, the cement-based composites have the advantage of outstanding interfacial combination and excellent interface compatibility with civil engineering structures because of the utilization of cement as matrix. These are easily prepared with low cost, along with stable properties. Especially their piezoelectric property is pretty satisfying for the application, in order to be made into cement-based transducer in the concrete structure.In this paper, PZT piezoelectric ceramics were mixed with cement to fabricate cement-based composites with excellent piezoelectric properties.0-3 cement-based piezoelectric composites were prepared by compressing process, which adopted different kinds of PZT piezoelectric ceramics as a functional phase, Portland cement and white cement as matrix, and were reinforced and modified by a small quantity of carbon black and CNTs. The main content and results are as follows.0-3 cement-based piezoelectric composites were prepared in this research, employing P41, P43, P51 and P52, four types of piezoelectric ceramic composite materials as functional phases and Portland cement as matrix, and the piezoelectric and dielectric properties of piezoelectric composites were also studied. The results showed that the composites adding P51 and P52 held better piezoelectric properties and higher dielectric constant but more dielectric loss and impedance accordingly. Piezoelectric properties of piezoelectric composites increased with the growth of the content of piezoelectric ceramic. Furthermore this paper analyzed different kinds of cement influencing the properties of the composites, which showed that Portland cement made slightly huge contribution, and the composites possessed almost the same dielectric properties among the three cement matrix.In this study, the effect of particle size on the piezoelectric and dielectric properties of 0-3cement-based piezoelectric composites was investigated. The piezoelectric composites were prepared by mixing and pressing the white cement and PZT powder with different average particle size ranged from 3μm to 482μm. It was found that the piezoelectric strain factor(d33), dielectric constant(εr), and electromechanical coupling coefficient(Kt) increased with the growth of the PZT particle size. However, the composites with larger PZT particles had higher dielectric loss(tanδ) than those with smaller particles. According to the results of XRD, SEM and MIP, the inferior d33,εr and Kt values of the composites with small PZT particle size were believed to due to the increase of porous interface between PZT particles and cement matrix. Whereas, the low value of the composites with small PZT particle size was attributed to its compacted microstructure.Lead zirconate titanate (Pb(Zro.52Ti0.4s)O3) nanopowder was prepared using a sol-gel process. The results of the DTA/TGA, XRD, laser particle size analysis and SEM studies indicated that the PZT powder calcined at 700℃had perovskite structure with an average crystallite diameter of 26.4 nm and an average agglomerate diameter of about 200 nm. The 0-3 cement/nano PZT composite were fabricated by pressing the mixture of white cement and nano PZT powders. The piezoelectric properties of the cement/nano PZT piezoelectric composites have been measured. Comparing to the cement/PZT composite made by incorporating the ground PZT particles, the cement/nano PZT composite showed a better piezoelectric activities.0-3 cement-based piezoelectric composites, fabricated from white cement, PZT powder and small amounts of carbon black, were exploited for potential applications in civil engineering. The nature of the aging and poling behavior of the carbon black/PZT/cement composites was investigated. It was shown that the use of a conductive carbon black phase can facilitate the poling process at room temperature. The influences of the carbon black on the piezoelectric and dielectric properties were studied as well. It was demonstrated that the piezoelectric sensitivities of the composites can be dramatically enhanced by incorporation of small amounts of carbon black, due to its conductivity. With a poling field of 4kV/mm and poling time of 20min, the d33,εr, tanδand Kt values of the composites containing 70vol.% PZT and 1.0vol.% carbon black were 28.5 pC/N,202.6,0.19 and 12.2%, respectively. In this research, the influence of the dispersion of carbon nanotubes to PZT/cement piezoelectric composites had been investigated.0-3 CNTs/PZT/cement piezoelectric composites were fabricated with the PZT powders, cement and a spot of CNTs utilizing the compacting method. The behaviors of cement-based piezoelectric composites embracing different contents of MWCNTs, and several methods of dispersion and purification of them were investigated on the piezoelectric and dielectric properties. The results showed that the CNTs influenced the piezoelectric properties of cement-based piezoelectric composites to certain extent. The Fenton/UV method was a better method to disperse the CNTs. Fenton/UV method could remove the amorphous impurities inside the CNTs thoroughly. And HNO3 oxidation and Fenton method both enable the introduction on CNTs surface of functional groups such as-C=O,-COOH,-OH and so on. There was a conductive network in PZT/cement piezoelectric composites with CNTs dispersed to improve the conductivity among them. It could improve the polarization efficiency of PZT particles and strengthen the piezoelectric and dielectric properties of PZT/cement piezoelectric composites. When CNTs content reached 0.10 wt.%, d33 of the composites could become 46 pC/N for the HNO3 oxidation method, but d33 of the composites could come to 54 pC/N for the Fenton/UV method at 0.15 wt.% CNTs.更多还原