SGER: Spinoidal Decomposition of Alnico Alloys in Confined Geometries

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TECHNICAL: Since their discovery, Alnico magnets have not lived up to their potential energy products due to the complex nature of spinodal decomposition which leads to coercivities below 2 kOe. The coercivity of these magnets is due to the shape anisotropy of fine Fe-Co rods which are produced through a spinoidal decomposition when the bulk sample is subjected to a high temperature heat treatment. The research here will allow us to study the size and shape dependence of spinodal decomposition in Alnico alloys under confined geometry in the form of nanoparticles, nanorods and thin films. PI will then use this information to tailor the properties of these magnets to values approaching those predicted by theoretical models. The aim of this research is to develop magnets with coercivity above 4 kOe. This is a high risk project since nobody so far has succeeded in getting coercivity greater than 2 kOe. This transformative project is also very interesting scientifically since it is focused on the size and shape dependence of spinodal decomposition and will provide valuable information on volumetrically constrained phase transformations. NON-TECHNICAL: The potential pay-off of this high risk undertaking will revolutionize the field of permanent magnets if successful. Coercivity in the range of 4-6 kOe, would allow the development of Alnico magnets with energy products in the range of 30-35 MGOe, comparable to the values of the expensive Sm-Co rare earth magnets. This will have a significant impact in the industry based on their projected lower cost (they do not contain any of the expensive rare earths), better high temperature properties, corrosion resistance and mechanical strength. The ability to nano-engineer permanent magnets from systems of nanoparticles would not only provide the opportunity to test the theoretical models already in the literature but will open the door for lighter and more powerful magnets that would open the door for many new applications. The interdisciplinary nature of the research will establish collaborations with other departments including Materials Science and Chemistry. The PI will use most of this grant to support a graduate student, a part-time undergraduate and one local high school student for the summer. Special emphasis will be given to minority and underrepresented groups. Through the Network of Undergraduate Collaborative Learning Experiences for Underrepresented Scholars (NUCLEUS) program the Magnetics lab participates in a campus wide effort to recruit underrepresented groups to the physical sciences whilst expanding our own horizons.