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首页> 外文学位 >Processing of lead magnesium niobate -lead titanate by a novel coating approach.
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Processing of lead magnesium niobate -lead titanate by a novel coating approach.

机译：通过新颖的涂覆方法处理铌酸铅镁-钛酸铅。

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摘要

Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) is an important ferroelectric material that has outstanding room temperature dielectric constant and electro-mechanical coefficient. Unlike most other ferroelectric materials, PMN-PT is difficult to prepare because of the formation of unwanted pyrochlore phase. Many methods of PMN-PT preparation have been developed to overcome this problem over the past decades. The remaining major problems for these methods are the high sintering temperature of 1200°C and the complex processing steps. In this thesis, a new coating method is introduced for PMN-PT processing. This method involves coating Mg(OH) 2 on the surface of Nb2O5 particles to increase the mixing of chemical components and enhance the complete transformation from pyrochlore phase to perovskite phase. With this method, the processing is simplified to only one-step calcination for PMN-PT powder preparation and one-step sintering for PMN-PT dense part preparation. At the same time, the sintering temperature is decreased to 1000°C. To gain fundamental understanding on the colloidal coating process, a modified SAK simulation model was developed. In powder processing, it was shown that smaller particle size and better powder configurations were the reasons for eliminating pyrochlore phase. On the other hand, smaller particle size and reactive sintering are responsible for the lower temperature sintering. Finally, processing optimization study showed that 0–2 at.% PbO excess is the ideal composition for high quality PMN-PT preparation.
机译：Pb（Mg 1/3 Nb 2/3 ）O 3 -PbTiO 3 （PMN-PT）为一种重要的铁电材料，具有出色的室温介电常数和机电系数。与大多数其他铁电材料不同，由于形成不需要的烧绿石相，PMN-PT难以制备。在过去的几十年中，已经开发了许多PMN-PT制备方法来克服此问题。这些方法的剩余主要问题是1200℃的高烧结温度和复杂的加工步骤。本文介绍了一种用于PMN-PT加工的新型涂层方法。该方法包括在Nb 2 O 5 颗粒的表面上涂覆Mg（OH） 2 ，以增加化学成分的混合并增强其完整性。从烧绿石相转变为钙钛矿相。使用这种方法，将处理简化为仅制备PMN-PT粉末的一步煅烧和仅一步烧结的PMN-PT致密零件的烧结过程。同时，烧结温度降低到1000℃。为了获得对胶体涂层工艺的基本了解，开发了改进的SAK模拟模型。在粉末加工中，显示出较小的粒度和较好的粉末构型是消除烧绿石相的原因。另一方面，较小的粒度和反应性烧结是造成较低温度烧结的原因。最后，工艺优化研究表明，过量的0–2 at。％PbO是高质量PMN-PT制备的理想成分。

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  • 作者

    Gu, Huiming.;

  • 作者单位

    Drexel University.;

  • 授予单位 Drexel University.;
  • 学科 Engineering Materials Science.; Chemistry Inorganic.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 153 p.
  • 总页数 153
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;无机化学;
  • 关键词

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