RUI: Studies of the Heating and Sintering of Powdered Metals in Separate Electric and Magnetic Fields Using a Single Mode Microwave Cavity

该RUI奖由材料研究部授予位于大学公园的宾夕法尼亚州立大学，解决了两个问题：第一，金属粉末压块如何通过微波辐射如此有效地加热，第二，烧结的初始阶段是否符合传统模型，或者解释是否需要特定的微波模型？这两个问题将由阿尔图纳的宾夕法尼亚州立大学的齐默尔曼教授和研究小组在三个方面加以解决：（a）使用谐振腔技术对粉末金属压块的复介电常数和磁导率作为温度、颗粒尺寸、颗粒氧化和堆积密度的函数进行经验研究;（B）使用单模微波系统识别电场和磁场对加热和烧结的单独贡献;和（c）通过用光学和扫描或透射电子显微镜（SEM或TEM）检查直接检查加热（烧结）样品来评价烧结的第一阶段。由于这些材料的工业重要性，重点将放在铜，金和钨的过渡金属粉末以及铁和钴的铁磁性粉末上。通过这些研究获得的温度分布和能量沉积的知识将促进对微波烧结过程的理解，该项目将为粉末金属的电磁特性和微波加热烧结提供新的知识，这将在工业上具有广泛的应用。此外，该项目包括学生的培训和发展，并使教师和博士后研究人员的专业发展。这项工作是在一个研究环境中为本科生谁是研究生学习或工业工作的应用科学和工程准备。大学B.S.在科学，机电工程技术和材料的应用科学拟议的学位课程将大大受益于这个本科研究计划。学生将获得教育效益，同时为研究的成功做出重大贡献。他们的经验将最终通过在区域或国家会议上的口头和海报介绍来传播成果。这些研究补充了位于大学公园的宾夕法尼亚州立大学材料研究所的工作，本科生将从与位于大学公园的宾夕法尼亚州立大学的其他学生，博士后研究人员和教师的思想交流中受益。

This RUI award by the Division of Materials Research to Pennsylvania State University at University Park addresses two questions: first, how metal powder compacts are heated so efficiently by microwave radiation and, second, if the initial stage of sintering fits conventional models or does the explanation require a microwave-specific model? These two questions will be addressed by Professor Zimmerman and the team at Pennsylvania State University at Altoona on three fronts: (a) an empirical study of the complex permittivity and permeability of powder metal compacts as a function of temperature, particle size, particle oxidation, and packing density using resonant cavity techniques; (b) identification of the separate contributions of the electric and magnetic fields to the heating and sintering using a single-mode microwave system; and (c) evaluation of the first stage of sintering by direct examination of heated (sintered) samples by inspection with both optical and scanning or transmission electron microscopy (SEM or TEM). The focus will be on transition metal powders of copper, gold, and tungsten and ferromagnetic powders of iron and cobalt, due to the industrial significance of these materials. The knowledge of the temperature distribution and energy deposition gained from these present studies would advance understanding of the microwave sintering process.This project would provide new knowledge on the electromagnetic properties and microwave heating and sintering of powdered metals, which could have wide applications in industry. In addition, the project includes training and development of students and enables professional development of faculty and a postdoctoral researcher. This work is in a research environment for undergraduate students who are preparing for graduate studies or industrial work in the applied sciences and engineering. The universities B.S. degrees in Science, Electromechanical Engineering Technology and a proposed degree program in Applied Science of Materials will benefit greatly from this undergraduate research program. The students will reap educational benefits while making significant contributions to the success of the research. Their experience will culminate in the dissemination of results with oral and poster presentations at regional or national meetings. The studies complement work at the Materials Research Institute at Penn State University in University Park and the undergraduate students will benefit from an exchange of ideas with other students, post- doctoral researchers, and faculty at Penn State University in University Park.