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Single-walled carbon nanotube-silicon nitride composites.

机译：单壁碳纳米管-氮化硅复合材料。

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摘要

Colloidal processing methods were developed in order to disperse highly concentrated 1.0, 2.0, and 6.0 vol% single-walled carbon nantoube (SWNT)-Si 3N4 aqueous composite suspensions. Interparticle pair potentials were developed between individual Si3N4 particles and SWNT bundles by coating them with cationic surfactant molecules of cetyltrimethylammonium bromide (CTAB). Zeta potential, viscosity, and sedimentation measurements were conducted on SWNTs and Si3N4 particle suspensions in order to optimize the pH and amount of adsorbed CTAB. The composite suspension viscosity was pH sensitive and adjusted accordingly before consolidation into three-dimensional solid parts using a rapid prototyping fabrication method called robocasting. High-density composites were produced using spark plasma sintering and structurally intact SWNTs were directly observed in the final sintered microstructure using scanning electron microscopy and Raman spectroscopy. When processed with SWNTs the highly insulative ceramic became electrically conductive and resulted in increased grindability for the otherwise hard to machine ceramic. The high hardness, fracture toughness and density of Si 3N4 was maintained for the composite due to the detailed development of colloidal processing and sintering methods used during fabrication. In addition, the thermal conductivity of the ceramic was reduced with the incorporation of well-dispersed SWNTs. Indentation load studies on the composites revealed sub-surface chipping and deformation around the indent before radial crack development indicating a degree of damage tolerance over the monolith. Along the wake of the crack SWNTs were also observed bridging the crack therefore showing their potential to act as toughening agents in brittle ceramics.
机译：为了分散高浓度的1.0、2.0和6.0％（体积）的单壁碳纳米管（SWNT）-Si 3N4水性复合悬浮液，开发了胶体加工方法。通过用十六烷基三甲基溴化铵（CTAB）的阳离子表面活性剂分子包被，在单独的Si3N4颗粒和SWNT束之间形成颗粒间对电位。在SWNT和Si3N4颗粒悬浮液上进行了Zeta电势，粘度和沉降测量，以优化pH和CTAB吸附量。复合悬浮液的粘度对pH敏感，并在使用称为robocasting的快速原型制造方法固结为三维固体零件之前进行了相应的调整。使用火花等离子体烧结生产高密度复合材料，并使用扫描电子显微镜和拉曼光谱在最终的烧结微观结构中直接观察到结构完整的单壁碳纳米管。当用SWNTs处理时，高绝缘性的陶瓷变成导电的，并提高了原本难以加工的陶瓷的可磨性。由于在制造过程中使用的胶体加工和烧结方法的详细发展，使复合材料保持了较高的硬度，断裂韧性和Si 3N4密度。另外，掺入分散良好的单壁碳纳米管会降低陶瓷的热导率。复合材料的压痕载荷研究表明，在径向裂纹发展之前，压痕周围存在亚表面的碎裂和变形，表明在整体结构上的损伤容忍度。沿着裂纹的开始，还观察到单壁碳纳米管桥接裂纹，因此显示出它们在脆性陶瓷中作为增韧剂的潜力。

著录项

  • 作者

    Corral, Erica Lorrane.;

  • 作者单位

    Rice University.;

  • 授予单位 Rice University.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 143 p.
  • 总页数 143
  • 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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