Fe powders show tremendous potential for improving the efficiency and reducing the cost of electric motors. However, the lack of a coating material, which is mechanically durable, electrically insulating, and magnetic, is a fundamental obstacle to the implementation of Fe powders in electromagnetic cores. In this project, candidate oxide coatings, prepared by molecular beam epitaxy, will be identified by investigating the magnetic and structural properties of oxide-Fe interfaces in the form of thin film heterostructures. The combination of atomic scale microscopy and neutron scattering techniques will reveal how the atomic structure and magnetic behavior of the interfaces are correlated, providing unprecedented insight into how defects, strain, and local stoichiometry alter interfacial magnetism. Based on these results, optimal coatings and processing conditions will be identified for use in Fe-powder-based electromagnetic devices. The work addresses known hurdles within existing industrial production environments and is strategically targeted towards the next generation materials and processing necessary for the future direction of electromagnetic devices.
This research will have both educational and economic impacts. Outreach programs will be developed to expose students to job opportunities in our growing energy efficient industry and economy. These will bring together groups of students from West Philadelphia (predominantly minority) schools for workshops and career fairs associated with electric motors, hybrid vehicles, and alternative energy. Development and understanding of these new materials will provide a tangible benefit to society. Electric motors have over a 50% increase in energy conversion over internal combustion engines, and thus, the development of these materials for automotive applications steer the automotive industry away from the dependence on fossil fuels and drives down consumer costs. This will translate into the development of the skills and knowledge for upcoming engineers and technical professionals that will become involved in the automotive, aerospace and industrial sectors.
Thin film heterostructures of Fe/MgO, Fe3O4/MgO, and Fe/Fe3O4/MgO were successfully deposited using MBE and analyzed for magnetic properties using a custom-built Magneto-optical Kerr effect (MOKE) magnetometer, vibrating sample magnetometry (VSM), and ferromagnetic resonance (FMR). X-ray diffraction (XRD) and reflectivity (XRR) analysis were obtained to determine layer thickness, crystalline, and composition. TEM images were captured for interfacial analysis of internal defects and strain. Iron powders were coated with electrically insulating material, alumina (Al2O3) or magnetite (Fe3O4), then subsequently compacted and cured. The dependence of size and material of milling media, greatly affects the structural, mechanical, and magnetic properties ball-milled powders. Larger media balls allow for more deformation and more contamination to be present in milled powders. Longer milling times essentially have comparable effects. Both outcomes lead to reduced magnetization saturation; however, have improved properties compared to powder coated with organic materials (polymers, resins, etc.). A patent has been filed for the design and processing methods of magnetically coated ferrous powders as soft magnetic composites. The developments made have a large impact on the energy economy. Improving the processing procedures for development of soft magnetic composites greatly reduces manufacturing cost and time by conventional powder metallurgy techniques. Replacing traditional silicon-steel laminations with ferrous powder soft magnetic composites, greatly improves efficiency in manufacturing by producing less waste and requiring less energy to construct. Three graduate students, a post-doc, and various undergraduate students have been supported by this grant, including a female PI, female grad student, and a female undergraduate student. Numerous presentations and posters have been promoted for this research at noteworthy conferences like TMS, MS&T, MRS, and PowderMet. PI’s and students associated with this grant have been involved in numerous outreach programs, which include being leaders and presenters at the Philadelphia Chapter ASM Materials Camps held at Drexel University each summer, volunteers at Philly’s and Drexel’s Materials Science Days and Science Saturdays at Drexel University, as well as various opportunities in the Materials Science Department at Drexel University. Two students funded by this grant have also had the opportunity to attend the Winter School for High Resolution Microscopy at Arizona State University, and visit various laboratories such as National Insititute of Standards & Technology (NIST), Oak Ridge National Laboratory (ORNL), US Army Research Lab (ARL), and Argonne National Laboratory. Several students involved have been teaching assistants for different engiineering and materials science courses at Drexel University, ranging from freshman to senior level classes.
