Electromagnetic Fields Produced by Self-Propagating High-Temperature Synthesis (SHS)

自传播高温合成 (SHS) 产生的电磁场

• 批准号: 0003015
• 负责人: Dan Luss
• 金额: $ 29.19万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2004-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0003015&HistoricalAwards=false
• 关键词: Electromagnetic; Fields; Produced; Self; Propagating

Recent experiments have shown that a transient electrical voltage ( electrochemical effect) and a weak magnetic field ( chemomagnetism) form during self-propagating high-temperature synthesis (SHS). This is a combined experimental and theoretical study of the electrochemical effect and chemomagnetism induced by combustion processes with the goals of elucidating their origin, sign, magnitude, and shape, and providing a means to predict them and their impact. Similar reactions, such as oxidation or nitridation of a metal, are done with metals from a row or group of the periodic table to give possible correlations with electronic structure, oxygen affinity, and oxidation state. Experiments are conducted at various gas pressures, sample compositions, porosities and particle sizes to determine the effects of these factors as well as the relationships between the induced signals and reaction temperature and combustion wave velocity. The small magnetic fields are measured with a high-Tc superconducting quantum interface device (SQUID). A model to predict the electrical potential formation is developed, initially based on the assumption that an electrical change is formed in individual particles due to a gradient of ions across a product layer formed during combustion. The model predicts combustion wave velocity and profiles of voltage, temperature, oxygen concentration, and metal conversion in the combustion and post-combustion zones. The predicted voltage profile is then used to calculate the induced magnetic signal. The model in revised on the basis of the experimental results.

最近的实验表明，在自蔓延高温合成（SHS）过程中会形成瞬态电压（电化学效应）和弱磁场（化学磁性）。 这是一个结合实验和理论研究的电化学效应和化学磁性引起的燃烧过程的目的阐明其起源，符号，幅度和形状，并提供一种手段来预测它们和它们的影响。 类似的反应，例如金属的氧化或氮化，可以用周期表中的一行或一组金属进行，以给出与电子结构，氧亲和力和氧化态的可能相关性。 在不同的气体压力，样品组成，孔隙率和颗粒尺寸进行实验，以确定这些因素的影响，以及诱导信号与反应温度和燃烧波速度之间的关系。 用高温超导量子接口器件（SQUID）测量了小磁场。 一个模型来预测的电势形成的开发，最初基于的假设，即由于在燃烧过程中形成的产物层的离子的梯度，在单个颗粒中形成的电气变化。 该模型预测燃烧波的速度和档案的电压，温度，氧气浓度，和金属转化的燃烧和后燃烧区。 预测的电压分布然后用于计算感应的磁信号。 根据实验结果对模型进行了修正。