• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Reactive processing and mechanical properties of polymer derived silicon nitride matrix composites and their use in coating and joining ceramics and ceramic matrix composites.
【24h】

Reactive processing and mechanical properties of polymer derived silicon nitride matrix composites and their use in coating and joining ceramics and ceramic matrix composites.

机译：聚合物衍生的氮化硅基复合材料的反应加工和力学性能及其在陶瓷和陶瓷基复合材料的涂层和连接中的用途。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Use of preceramic polymers offers many advantages over conventional ceramic processing routes. Advantages include being able to plastically form the part, form a pyrolized ceramic material at lower temperatures and form high purity microstructures which are tailorable depending on property requirements. To date preceramic polymers are mostly utilized in the production of low dimensional products such as fibers since loss of volatiles during pyrolysis leads to porosity and large shrinkage (in excess of 30%). These problems have been partially solved by use of active fillers (e.g. Ti, Cr, B). The reactive filler converts to a ceramic material with a volume expansion and this increases the density and reduces shrinkage and porosity. The expansion of the reactive filler thus compensates for the polymer shrinkage if the appropriate volume fraction of filler is present in a reactive atmosphere (e.g. N2 or NH3). This approach has resulted in structural composites with limited success. The present research investigates the possibility of using filled preceramic polymers to form net shaped ceramic composite materials and to investigate the use of these unique composite materials to join and coat ceramics and ceramic composites.; The initial research focused on phase and microstructural development of bulk composites from the filled polymer/ceramic systems. A processing technique was developed to insure consistency between different samples and the most promising filler/polymer choices for this application have been determined. The processing temperatures and atmospheres have also been optimized.; The work covers processing and characterization of bulk composites, joints and coatings. With careful control of processing near net shape bulk composites were fabricated. Both ambient and high temperature strength and fracture toughness was obtained for these composite systems. The potential of using reactively filled preceramic polymers to process joints and coatings was also investigated. A critical thickness below which crack free joints/coatings could be processed was determined. Finally, mechanical properties of the joints and coatings at ambient and elevated temperatures (including oxidation studies) have been evaluated. The interfacial fracture behavior of the joints and coatings was also evaluated.
机译：与常规的陶瓷加工路线相比，使用陶瓷前的聚合物具有许多优势。优点包括能够塑性成形零件，在较低温度下形成热解陶瓷材料以及形成可根据性能要求定制的高纯度微结构。迄今为止，由于热解过程中挥发物的损失会导致孔隙率和大的收缩率（超过30％），因此陶瓷聚合物主要用于生产低维产品，例如纤维。通过使用活性填料（例如Ti，Cr，B）已部分解决了这些问题。反应性填料转化为具有体积膨胀的陶瓷材料，这增加了密度并减少了收缩率和孔隙率。因此，如果在反应性气氛中存在适当体积分数的填料（例如N 2 或NH 3 ），则反应性填料的膨胀可补偿聚合物的收缩。这种方法导致结构复合材料的成功有限。本研究调查了使用填充的陶瓷前聚合物形成网状陶瓷复合材料的可能性，并研究了使用这些独特的复合材料来连接和涂覆陶瓷及陶瓷复合材料的方法。最初的研究重点是从填充的聚合物/陶瓷系统中进行本体复合材料的相和微观结构开发。开发了一种加工技术以确保不同样品之间的一致性，并确定了针对该应用的最有希望的填料/聚合物选择。加工温度和气氛也已优化。这项工作涵盖了块状复合材料，接缝和涂层的加工和表征。通过仔细地控制接近净形的块状复合材料。这些复合体系既获得了环境强度，高温强度，又具有断裂韧性。还研究了使用反应性填充的陶瓷前体聚合物加工接缝和涂层的潜力。确定了临界厚度，在该临界厚度以下可以加工无裂纹的接缝/涂层。最后，评估了在环境温度和高温下的接头和涂层的机械性能（包括氧化研究）。还评估了接头和涂层的界面断裂行为。

著录项

  • 作者

    Stackpoole, Margaret Mary.;

  • 作者单位

    University of Washington.;

  • 授予单位 University of Washington.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2002
  • 页码 249 p.
  • 总页数 249
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号