CAREER: Manufacturing Rare Earth Permanent Magnets via Three-dimensional Printing and Decomposition of Hydrogels

This Faculty Early Career Development (CAREER) grant supports research that focuses on understanding a new manufacturing process that fabricates rare earth permanent magnets via additive manufacturing - three-dimensional printing (3D-printing - and decomposition of hydrogels. Rare earth permanent magnets exhibit significantly superior magnetic properties compared to non-rare earth permanent magnets and have a wide range of applications, including high-performance electric motors, power generators, magnetic resonance imaging, and electric vehicles.

However, current manufacturing processes for rare earth permanent magnets are complex, expensive, energy intensive and produce simple shapes. To address these challenges, this research project looks to develop a new manufacturing process that involves 3D-printing of hydrogel containing rare-earth elements to create complex three-dimensional structures.

These 3D hydrogel structures are subsequently decomposed and then heated at high temperature to produce fully dense rare earth permanent magnets exhibiting excellent magnetic and mechanical properties. If successful, this new technique will allow for the fabrication of rare earth permanent magnets with different complex geometries and near-zero defects.

The ability to manufacture complex 3D rare earth permanent magnets is of interest to many industries, such as power and energy, aerospace and automotive, electronics and optoelectronics, healthcare and biomedical which benefits the U.S. economy and promotes prosperity This research is complemented by establishing interdisciplinary educational and outreach programs founded on project-based learning and free online course development.

The specific goal of this research is to discover the complex composition-processing-microstructure-property relationships in rare earth permanent magnets fabricated via additive manufacturing and decomposition of rare earth containing hydrogels. The desired outcomes are rare earth permanent magnets with higher magnetic remanence, coercivity, and energy product than non-rare earth permanent magnets.

The objectives of this research are (1) the development of 3D printable hydrogel inks containing rare earth and other metallic elements, and (2) the understanding of the composition and microstructure evolutions during the decomposition of the 3D printed hydrogels and the formation of metallic phases. The decomposition steps involve calcination to multi-metal oxides, followed by reduction, sintering and annealing to fully dense rare earth permanent magnets with superior magnetic and mechanical properties.

The project aims to address the following research questions. (1) What are the mechanisms governing the rheological properties and printability of the new hydrogel inks? (2) What factors affect the composition and microstructure evolution during the decomposition of the 3D printed hydrogels? (3) What factors affect the types and rates of reactions during the formation of the rare earth permanent magnets?

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.