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Iowa State University (ISU) and Ames Laboratory (AL) researchers have developed a method to manufacture Ni-Co-Mn-Ti intermetallics with enhanced magnetocaloric properties. The resultant materials produce an extremely large magnetocaloric effect (MCE) with a modest magnetic field change. The MCE is nearly three times greater at near room temperature than the same material made via conventional processing.

Magnetocaloric materials undergo a change in temperature when subjected to the application and removal of a magnetic field. While a number of magnetocaloric materials have been discovered, most have not been commercialized. Reasons for this vary, but the cost of the raw material, weak magnetocaloric effect, and/or poor physical properties such as volumetric change in response to magnetic field and resulting brittleness have hampered development efforts.
ISU and AL researchers have discovered a method for making an intermetallic compound that improves the mechanical and magnetocaloric properties of the alloys. In addition, the researchers have substituted cheaper elements into the alloys to create an extended family of compounds. The method involves rapid solidification of the melt alloy, promoting a more homogenous mixture of the elements and a different microstructure compared to conventional casting methods. This technology enhances the magnetocaloric properties of Ni-Co-Mn-Ti-based intermetallics.

• Method provides up to 3x greater MCE compared to conventional methods.

• The properties of the materials prepared are highly tunable through changing materials’ compositions.

• The materials’ operation temperatures can be further tuned by annealing at different temperatures.

• The materials are compatible with metal or polymeric binders and may be used to fabricate composite parts.

• Compositional variants could reduce cost.

• No need of heat-treatment.

Commercial magnetic refrigeration.

Patent(s) applied for