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首页> 外文学位 >Processing, properties, and application of textured 0.72lead(magnesium niobate)-0.28lead titanate ceramics.
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Processing, properties, and application of textured 0.72lead(magnesium niobate)-0.28lead titanate ceramics.

机译：0.72铅（铌酸镁）-0.28钛酸铅陶瓷的加工，性能和应用。

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摘要

In this study, XRD and electron backscatter diffraction (EBSD) techniques were used to characterize the fiber texture in oriented PMN-28PT and the intensity data were fit with a texture model (the March-Dollase equation) that describes the texture in terms of texture fraction (f), and the width of the orientation distribution (r). EBSD analysis confirmed the 001> orientation of the microstructure, with no distinguishable randomly oriented, fine grain matrix. Although XRD rocking curve and EBSD data analysis gave similar f and r values, XRD rocking curve analysis was the most efficient and gave a complete description of texture fraction and texture orientation (f = 0.81 and r = 0.21, respectively). XRD rocking curve analysis was the preferred approach for characterization of the texture volume and the orientation distribution of texture in fiber-oriented PMN-PT.;The dielectric, piezoelectric and electromechanical properties for random ceramic, 69 vol% textured, 81 vol% textured, and single crystal PMN-28PT were fully characterized and compared. The room temperature dielectric constant at 1 kHz for highly textured PMN-28PT was epsilonr ≥ 3600 with low dielectric loss (tan delta = 0.004). The temperature dependence of the dielectric constant for 81 vol% textured ceramic followed a similar trend as the single crystal PMN-28PT up to the rhombohedral to tetragonal transition temperature (TRT) at 104°C. 81 vol% textured PMN-28PT consistently displayed 60 to 65% of the single crystal PMN-28PT piezoelectric coefficient (d33) and 1.5 to 3.0 times greater than the random ceramic d33 (measured by Berlincourt meter, unipolar strain-field curves, IEEE standard resonance method, and laser vibrometry). The 81 vol% textured PMN-28PT displayed similarly low piezoelectric hysteresis as single crystal PMN-28PT measured by strain-field curves at 5 kV/cm. 81 vol% textured PMN-28PT and single crystal PMN-28PT displayed similar mechanical quality factors of QM = 74 and 76, respectively. The electromechanical coupling (k 33) of 81 vol% textured PMN-28PT (k33 = 0.79) was a significant fraction of single crystal (k33 = 0.91) and was higher than a commercial PMN-PT ceramic (k33 ∼ 0.74).;The nonlinearity of the dielectric and piezoelectric response were investigated in textured ceramics and single crystal PMN-28PT using the Rayleigh approach. The reversible piezoelectric coefficient was found to increase significantly and the hysteretic contribution to the piezoelectric coefficient decreased significantly with an increase in texture volume. This indicates that increasing the texture volume decreases the non-180° domain wall contribution to the piezoelectric response in PMN-28PT.;Finally, 81 vol% textured ceramics were also integrated into a Navy SONAR transducer design. In-water characterization of the transducers showed higher source levels, higher in-water coupling, higher acoustic intensity, and more bandwidth for the 81 vol% textured PMN-28PT tonpilz single elements compared to the ceramic PMN-28PT tonpilz element. In addition, an 81 vol% textured PMN-28PT tonpilz element showed large scale linearity in sound pressure levels as a function of drive level under high drive conditions (up to 2.33 kV/cm). The maximum electromechanical coupling obtained by the 81 vol% textured PMN-28PT transducer under high drive conditions was keff = 0.69. However, the resonance frequency shifted significantly during high drive tests (Deltafs = -19% at 3.7 kV/cm), evidence of a "soft" characteristic of the 81 vol% textured PMN-28PT, possibly caused by Sr2+ from the template particles.;The results suggest there are limitations on the preload compressive stress (and thus drive level) for these textured ceramics, but this could be addressed with compositional modifications. The dielectric, piezoelectric and electromechanical properties have been significantly improved in textured PMN-PT ceramics of this study. Furthermore, scale-up in processing for incorporation into devices of highly textured ceramics with reproducible texture (and hence narrow properties distribution) was achieved in these materials. SONAR applications could benefit from textured ceramic parts because of their ease of processing, compositional homogeneity and potentially lower cost. (Abstract shortened by UMI.)
机译：在这项研究中，XRD和电子背散射衍射（EBSD）技术用于表征定向PMN-28PT中的纤维织构，并且强度数据与描述织构的织​​构模型（March-Dollase方程）拟合分数（f）和取向分布的宽度（r）。 EBSD分析证实了微观结构的<001>取向，没有可分辨的随机取向的细晶粒基体。尽管XRD摇摆曲线和EBSD数据分析给出了相似的f和r值，但XRD摇摆曲线分析是最有效的，并且完整描述了纹理分数和纹理取向（分别为f = 0.81和r = 0.21）。 XRD摇摆曲线分析是表征纤维定向PMN-PT中织构体积和织构取向分布的首选方法;无规陶瓷的介电，压电和机电性能，织构为69％，织构为81％，和单晶PMN-28PT进行了充分表征和比较。高度织构化的PMN-28PT在1 kHz时的室温介电常数为ε≥3600，介电损耗低（tanδ= 0.004）。 81vol％织构陶瓷的介电常数与温度的相关性与单晶PMN-28PT相似，直至104°C时由菱形向四边形的转变温度（TRT）呈趋势。 81vol％织构化的PMN-28PT始终显示出60％至65％的单晶PMN-28PT压电系数（d33），是随机陶瓷d33的1.5至3.0倍（通过Berlincourt测量，单极应变场曲线，IEEE标准）共振法和激光振动法）。 81 vol％织构的PMN-28PT表现出与单晶PMN-28PT相似的低压电滞后性，通过5 kV / cm的应变场曲线测得。 81％（体积）织构化的PMN-28PT和单晶PMN-28PT表现出相似的机械品质因数QM = 74和76。 81％（体积）织构化PMN-28PT（k33 = 0.79）的机电耦合（k 33）是单晶的重要部分（k33 = 0.91），高于商用PMN-PT陶瓷（k33〜0.74）。使用瑞利方法研究了纹理陶瓷和单晶PMN-28PT中介电和压电响应的非线性。发现随着纹理体积的增加，可逆压电系数显着增加，并且对压电系数的滞后贡献显着降低。这表明增加纹理体积会降低非180°畴壁对PMN-28PT中压电响应的贡献。最后，还将81％（体积）的纹理陶瓷集成到Navy SONAR换能器设计中。与陶瓷PMN-28PT tonpilz元件相比，换能器的水中特性显示81vol％纹理化PMN-28PT tonpilz单个元件具有更高的源电平，更高的水耦合，更高的声强和更大的带宽。此外，在高驱动条件下（最高2.33 kV / cm），81vol％织构化的PMN-28PT tonpilz元件在声压级上显示出大规模线性关系，该线性度是驱动级的函数。在高驱动条件下，由81％（体积）织构化的PMN-28PT换能器获得的最大机电耦合为keff = 0.69。但是，在高驱动测试期间，共振频率发生了显着变化（在3.7 kV / cm时Deltafs = -19％），这证明了81 vol％织构化PMN-28PT的“软”特性，可能是由模板颗粒中的Sr2 +引起的。 ；结果表明，这些纹理陶瓷在预紧压缩应力（以及驱动水平）上存在局限性，但是可以通过修改成分来解决。在这项研究的纹理化PMN-PT陶瓷中，介电，压电和机电性能已得到显着改善。此外，在这些材料中实现了工艺放大，以结合到具有可再现的质地（并因此具有窄特性分布）的高质感陶瓷装置中。 SONAR应用程序可以从纹理化陶瓷零件中受益，因为它们易于加工，成分均匀且成本更低。 （摘要由UMI缩短。）

著录项

  • 作者

    Brosnan, Kristen H.;

  • 作者单位

    The Pennsylvania State University.;

  • 授予单位 The Pennsylvania State University.;
  • 学科 Engineering Materials Science.;Physics Acoustics.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 246 p.
  • 总页数 246
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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