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首页> 外文会议>Ceramic microstructures : Control at the atomic level >MULLITIZATION BEHAVIOR OF ALPHA ALUMINA/SILICA MICROCOMPOSITE POWDERS
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MULLITIZATION BEHAVIOR OF ALPHA ALUMINA/SILICA MICROCOMPOSITE POWDERS

机译：氧化铝/二氧化硅微粉的抗蠕变性能

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摘要

The mechanism of mullite formation was investigated using submicrometer composite particles which consisted of alpha alumina cores and amorphous silica coatings. Mullitization behavior was monitored using X-ray diffraction analysis, differential thermal analysis, and scanning electron microscopy. The transformation occurred with an incubation period which was followed by stages of rapid mullite growth (up to ～70% conversion) and slower mullite growth. The first growth stage occurred primarily by nucleation and growth within the siliceous matrix. Available evidence indicates that the growth rate was controlled by dissolution of alumina in the siliceous phase. The second stage of mullitization occurred primarily by interdiffusion of alumina and silica through the mullite grains formed during the first stage. The transformation rate in the second stage was increased significantly by using mullite seed particles which produced smaller grain sizes during the first stage (and, thereby, decreased the interdiffusion distances needed to complete the reaction). This seeding approach allowed fabrication of bulk mullite samples with nearly 100% relative density and fine grain size (～0.4 μm) after heat treatment at only 1400℃ (2 h).
机译：使用亚微米级复合颗粒研究了莫来石的形成机理，该复合颗粒由α氧化铝核和无定形二氧化硅涂层组成。使用X射线衍射分析，差示热分析和扫描电子显微镜监测多晶化行为。转化发生在潜伏期，随后是莫来石快速生长（转化率高达70％左右）和莫来石生长较慢的阶段。第一生长阶段主要通过硅质基质内的成核和生长而发生。现有证据表明，生长速率受硅质相中氧化铝的溶解控制。莫来石的第二阶段主要是通过第一阶段形成的莫来石晶粒之间的氧化铝和二氧化硅相互扩散而发生的。通过使用在第一阶段产生较小晶粒尺寸的莫来石种子颗粒，第二阶段的转化率显着提高（从而减少了完成反应所需的相互扩散距离）。通过这种播种方法，仅在1400℃（2 h）的热处理后，就可以制造相对密度接近100％且晶粒细小（〜0.4μm）的块状莫来石样品。

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  • 来源
  • 会议地点 Berkeley CA(US)
  • 作者

    Michael D. Sacks; Keyun Wang; Gary W. Scheiffele; Nazim Bozkurt;

  • 作者单位

    Department of Materials Science and Engineering University of Florida Gainesville, FL 32611;

    Department of Materials Science and Engineering University of Florida Gainesville, FL 32611;

    Department of Materials Science and Engineering University of Florida Gainesville, FL 32611;

    Department of Materials Science and Engineering University of Florida Gainesville, FL 32611;

  • 会议组织
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 TQ174.01;
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