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Reconstructing oxide surfaces.

机译:重建氧化物表面。

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摘要

The work presented here is concentrated on surfaces and interfaces in alumina (Al2O3), anorthite (CaAl2Si 2O8), silica (SiO2) and rutile (TiO2). While each of these materials have different crystal structures and measurable properties, they all exhibit similar mechanisms for fundamental behavior.;The topics researched and discussed lead into each other. Faceting describes the movement of atoms to a lower energy configuration. While faceting of the surface is only considered, grain boundaries can be faceted. In cross-section, facets resemble grain boundary grooves. Grooves and ridges form where a grain boundary intersects the surface of a material. The grooves facilitate grain boundary migration and diffusion. The surface tension at the groove is governed by Young's equation, which balances the interfacial forces between the solid and vapor. Glass films can wet or dewet the surface a grain boundaries. Whether the film wets or dewets depends on the surface energy of the surface and the liquid. Capillary forces determine the type of dewet patterns formed on the surface. Again, the surface-vapor-liquid interfaces are governed by Young's equation. Liquid films at grain boundaries facilitate densification and grain boundary migration. Liquid phase sintering (LPS) uses capillary forces and the dissolution/reprecipitation process to sinter green compacts to a high density at lower temperatures. Capillary forces and surface tension can also cause the liquid film to penetrate or exude from the grain boundary. Various forms of microscopy have been used to characterize and relate these phenomena.
机译:这里介绍的工作集中在氧化铝(Al2O3),钙长石(CaAl2Si 2O8),二氧化硅(SiO2)和金红石(TiO2)的表面和界面上。尽管每种材料具有不同的晶体结构和可测量的特性,但它们都表现出相似的基本行为机理。刻面描述了原子向较低能量构型的运动。虽然仅考虑表面的刻面,但可以对晶界进行刻面。在横截面中,刻面类似于晶界槽。在晶界与材料表面相交的地方形成凹槽和脊。凹槽有助于晶界迁移和扩散。凹槽处的表面张力由Young方程控制,该方程平衡了固体和蒸气之间的界面力。玻璃膜可以润湿或润湿表面的晶界。膜是润湿还是润湿取决于表面和液体的表面能。毛细作用力决定了表面上形成的湿润图案的类型。同样,表面蒸气-液体界面由杨氏方程式控制。晶界处的液膜有助于致密化和晶界迁移。液相烧结(LPS)利用毛细作用力和溶解/再沉淀过程在较低的温度下将生坯烧结成高密度。毛细作用力和表面张力也会导致液膜渗透或从晶界渗出。已经使用各种形式的显微镜来表征和关联这些现象。

著录项

  • 作者

    Riesterer, Jessica Lori.;

  • 作者单位

    University of Minnesota.;

  • 授予单位 University of Minnesota.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 303 p.
  • 总页数 303
  • 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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