The importance of permanent magnets with rare earth metals has grown as emerging markets increase their demand for technologies made with these magnets. However, the constraints of rare earth suppliers, the environmental impact of the refining process, and price volatility have left consumers seeking alternative magnets for their applications. This has led to the search for a non-rare earth containing bulk material that will achieve similar magnetic strength and energy product as its rare earth counterpart. Mn-Ga binary alloys have shown promising magnetic properties, even though these alloys contain no rare-earth metals. Both theoretical predictions and experimental work showed that nanoscaled Mn-Ga samples, such as thin films, could have remarkable magnetic properties. Although the prediction provides a useful guideline, and thin films supply us with materials in some application, bulk materials are required for the majority of applications that require a strong magnetic field. To achieve nanostructure as obtained in thin films, we have performed research on making bulk (Mn1-x-yMy)Gax or Mn1-xGax-yMy alloys, where M is a substitutional metallic element, by dynamic mechanically milling and heat treatments. We report efforts to create hard magnetic materials for permanent magnet use. Using this process, materials with high coercivity, up to 18.8 kOe, have been fabricated. We demonstrate that we could enhance the remanence in bulk Mn based materials by engineering both the chemistry and fabrication routes. Fabrication was followed by a study into the coercivity mechanisms in these materials. / A Dissertation submitted to the Program in Material Science and Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2016. / July 12, 2016. / Hard magnetic material, Material science, Rare-earth free / Includes bibliographical references. / Ke Han, Professor Co-Directing Dissertation; Eric Hellstrom, Professor Co-Directing Dissertation; Don Levitan, University Representative; Naresh Dalal, Committee Member; Theo Siegrist, Committee Member; William Oates, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_366039 |
| Contributors | Brown, Daniel Ross (authoraut), Han, Ke (professor co-directing dissertation), Hellstrom, Eric (professor co-directing dissertation), Levitan, Don R. (university representative), Dalal, Naresh S. (committee member), Siegrist, Theo M. (committee member), Oates, William S. (committee member), Florida State University (degree granting institution), Graduate School (degree granting college), Program in Materials Science (degree granting department) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (104 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
Page generated in 0.0021 seconds