Investigation of Field Effects in Combustion Synthesis

这是一个电场对燃烧合成影响的研究。研究了电场通过热（焦耳加热）、质量输运（电输运）和电容（介电）贡献的影响。这项工作包括固体-固体和固体-液体反应系统。定量地确定了交流电流的大小和方向对界面处产物层成核和生长的影响。模型基于经电输运（电迁移）修正的质量输运通量方程。并对电场引燃过程进行了研究；需要对产品形成和同质性有更好的理解。这项工作的技术意义是巨大的：只有通过活化的SHS（自我持续高温合成）才能合成材料系统；包括纳米材料在内的SHS产品的组成和形态的改性；以及在诸如功能梯度材料（fgm）、热障涂层（tbc）和化学屏障涂层（CBCs）等应用中界面相互作用的修饰；一步法合成并致密化陶瓷材料。

This is an investigation of the influence of an electric field on combustion synthesis. The effects of an electric field through thermal (Joule heating), mass transport (electrotransport), and capacitive (dielectric) contributions are studied. The work includes both solid-solid and solid-liquid reaction systems. Effects of both the magnitude and direction of AC current on the nucleation and growth of product layers at the interfaces are determined quantitatively. Models are based on mass transport flux equations modified by electrotransport (electromigration). The process of ignition by an electric field in also studied; a better understanding of product formation and homogeneity is desired.The technological implications of this work are large: synthesis of materials systems that are achievable only by activated SHS (self-sustained high-temperature synthesis); modification of composition and morphology of SHS products including nanomaterials; and modification of interfacial interactions in such applications as functionally graded materials (FGMs), thermal barrier coatings (TBCs), and chemical barrier coatings (CBCs); and one-step synthesis and densification of ceramic materials.