University of Pittsburgh scientists have developed a novel method to prepare particulates for Mn-Al alloy permanent magnets (PMs) through severe plastic deformation. Using this deformation process with end-milling and subsequent thermal annealing, it is possible to produce e-phase particles with micron scale external dimensions and self-similar shapes with composition 54 atomic precent (at.%) Mn and 46 at.% Al. These particles can then be used to prepare t-phase based Mn-Al particulates with enhanced permanent magnetic properties for a variety of applications.
Description
There is a growing global need for PMs as these are critical components in clean energy technologies such as renewable energy generation. Mn-Al PM alloys can have large uniaxial magnetic anisotropy and high saturation magnetization leading to a theoretical maximum magnetic energy product, (BH)max?12MGOe. Optimization of production could lead to lower energy requirements and more sustainable alternatives to existing PMs which require rare-earth elements (REE) increasing the availability of cost-effective PMs.
Applications
• Electric and hybrid vehicles
• Permanent magnets
• Wind turbines and renewable energy generation
Advantages
Currently, PMs are produced using alloys containing REE, e.g., NdFeB, which offer maximal (BH)max up to ?55 MGOe. However, instability in global supply chains, an increased demand for REE, and geopolitical considerations around mine locations, all increase the cost of REE and there is a need for lower cost, sustainable alternatives. In this novel approach, Mn-Al alloys are used. These elements are in abundant global supply and may mitigate against supply chain issues associated with REE. Using the single-pass plastic deformation process by end-milling can lead to the production of particulate precursors for Mn-Al alloy-based permanent magnets. The low cost of the starting materials, the efficiency of a single-pass process (i.e., avoiding Mn losses to oxide formation conserving the Mn and Al ratios in the alloy), and the lower number of processing steps and time required, mean Mn-Al PMs could be low cost, sustainable alternatives to existing PMs to meet the global need.
Invention Readiness
Currently in the concept phase, but research demonstrated that modification of end-milling processes (e.g., tool spindle speed, radial, and axial depth of cut) could effectively produce e-phase Mn-Al particulates. These e-phase Mn-Al particulates demonstrated (BH)max = 4.2 MGOe using rotational tool speed of 4200 RPM and annealing for 20 min at 673K. These particulates could potentially be used for the preparation of t-phase containing PMs.
IP Status
Patent Pending
