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Metastable zirconia-yttria-alumina ceramics: Structure, processing and properties.

机译：亚稳态氧化锆-氧化钇-氧化铝陶瓷：结构，加工和性能。

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摘要

Metastable phases of zirconia-yttria-alumina produced by atmospheric plasma spray and subsequent quenching were studied. Two kinds of quenching methods were used: water quenching and splat quenching. Quenching rates were estimated to be 104°C/s for water quenching and between 105–107°C/s for splat quenching. Five compositions of sprayed dried powders (pure alumina, TZ3Y20A, TZ3Y57A, TZ3Y80A and pure zirconia) were plasma sprayed and quenched. The phases and microstructures of the plasma sprayed powders and thin films were investigated by XRD and FESEM. It was found that at different compositions and quenching rates, different high temperature phases formed. These phases are metastable at room temperature and can be in the form of an extended solid solution phase, an intermediate phase, or an amorphous structure. The grain sizes of the metastable phases are below 50 nm, as determined by XRD peak broadening. At the eutectic composition, zirconia-rich fibers (50 nm in diameter) uniformly distributed in an alumina-rich matrix were observed. 2-D and 3-D metastable phase diagrams were constructed to explain the metastable phase formation.; Plasma spraying can be used to fabricate ceramic nanocomposites either by pressure-assisted sintering or spray forming of the metastable powders. Mechanical properties of TZ3Y20A specimens produced by plasma spray forming on steel substrates were studied. The dependence of the 4-point bend strength on plasma spray parameters was studied by a 26-2 statistical experimental design. It was found that the bend strength was sensitive to both standoff distance and scanning speed.; The results of study show much promise in applications of the metastable ceramics. Firstly, homogeneous nucleation and growth of stable phases during sintering and high creep rate at elevated temperatures will result in uniformly dense nanoceramic composites. Secondly, extended solid solutions of rare earth elements in glass will greatly enhance the optical properties. Thirdly, reduced phase transformation temperatures will also find their applications in ceramic processing.
机译：研究了通过大气等离子喷涂和随后的淬火产生的氧化锆-氧化钇-氧化铝的亚稳相。使用了两种淬火方法：水淬和飞溅淬火。水淬的淬火速度估计为10 4 °C / s，而水淬的淬火速度为10 5 –10 7 °C / s 。等离子喷涂五种喷雾干燥粉末（纯氧化铝，TZ3Y20A，TZ3Y57A，TZ3Y80A和纯氧化锆）。用XRD和FESEM研究了等离子喷涂粉末和薄膜的相和微观结构。发现在不同的组成和淬火速率下，形成了不同的高温相。这些相在室温下是亚稳态的，并且可以是扩展的固溶体相，中间相或无定形结构的形式。通过XRD峰展宽确定，亚稳相的晶粒尺寸在50 nm以下。在低共熔组成下，观察到在富含氧化铝的基质中均匀分布的富含氧化锆的纤维（直径为50 nm）。构造了2-D和3-D亚稳态相图以解释亚稳态相的形成。等离子喷涂可用于通过压力辅助烧结或喷涂形成亚稳态粉末来制造陶瓷纳米复合材料。研究了等离子喷涂在钢基材上制备的TZ3Y20A试样的力学性能。通过2 6-2 统计实验设计研究了四点弯曲强度对等离子喷涂参数的依赖性。发现弯曲强度对支座距离和扫描速度均敏感。研究结果显示了亚稳陶瓷的应用前景。首先，在烧结过程中均匀成核和稳定相的生长以及在高温下的高蠕变速率将导致均匀致密的纳米陶瓷复合材料。其次，玻璃中稀土元素的扩展固溶体将大大提高光学性能。第三，降低的相变温度还将在陶瓷加工中得到应用。

著录项

  • 作者

    Zhou, Xinzhang.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 142 p.
  • 总页数 142
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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