Investigation of Field Effects in Combustion Synthesis

本文研究了电场对燃烧合成的影响。 电场通过热（焦耳加热），质量传输（电传输），电容（介电）的贡献的影响进行了研究。 本工作包括固-固和固-液两个反应体系。 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。 模型是基于质量传输通量方程修改电迁移（电迁移）。 本文还研究了电场点火的过程，希望能对产物的形成和均匀性有更好的理解。这项工作的技术意义是巨大的：合成只有通过活化SHS才能实现的材料体系（自维持高温合成）;包括纳米材料在内的SHS产物的组成和形貌的改性;以及在诸如功能梯度材料（FGM）、热障涂层（TBC）和化学阻挡涂层（CBC）等应用中的界面相互作用的改性;以及陶瓷材料的一步合成和致密化。

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.