Sticking with magnets topic.
While the meteor magnet
tetrataenite (first reported 1962) may still be of concern to some who think science akin to magic, another example might be germane to their comfort: MnBi permanent magnets. MnBi is the stoichiometric formula - the current magnet formula is ~50% of each.
These two articles "discuss" this more-recent PM "competitor" to NdFeB in more lay-friendly terms than below:
Improving rare-earth-free magnets through mic | EurekAlert!Improved rare-earth-free magnets can’t be touched - Materials TodayFor those more interested:
Basically MnBi first reported in 1992
ABSTRACT
The magnetic properties of the low-temperature phase of MnBi, prepared by rapid solidification, have been measured in a pulsed field over the temperature range 80–625 K. The anisotropy field, obtained by the singular-point-detection technique, is found to increase with temperature and has a maximum value of 9 T at 530 K. A fit to the saturation-magnetization measurement gives a virtual Curie point of 775 K. The coercive field is fitted by a hybrid domain-wall-pinning theory which yields, at 300 K, a domain-wall energy of 15.6 erg/cm2and a wall thickness of 70 Å. Below 200 K, the presence of a ferrimagnetic phase is detected. Its critical field associated with spin reversal is a convex function of temperature having a maximum value of 8 T at 120 K.
DOI:https://doi.org/10.1103/PhysRevB.46.14578
©1992 American Physical Society
Latest issue of JMMM shows there is still movement:
Engineering microstructure to improve coercivity of bulk MnBi magnet - ScienceDirect
MnBi is a candidate material for high-temperature magnets because of its increasing coercivity with increasing temperatures up to 255 °C. However, most efforts in fabricating bulk MnBi magnets have run into the problem of preserving the coercivity (Hcj) of its feedstock powders. About 70% of powder's Hcjwould be lost during the densification process. Our micromagnetic modeling shows that the coercivity mechanism of the MnBi bulk magnet is controlled by nucleation of the reversal magnetization domains, and the large Hcjloss that occurred during the powder consolidation process can be attributed to the inter-grain magnetic coupling. To attain a high Hcj, the grains in the MnBi bulk magnet must be separated with a non-magnetic grain boundary phase (GBP). To validate this GBP hypothesis, we engineered MnBi bulk magnets with two different types of GBP. The first type of GBP was created in-situ by precipitating excessive Bi from the grains; the second type was created ex-situ by coating silicates on the feedstock powders before the consolidation. While both GBP work, the ex-situ approach resulted in a better Hcjdue to a more uniform GBP distribution. The Hcjloss was reduced from 70% to 15%, and the (BH)maxof a warm sintered bulk magnet reached 8.9 MGOe.
SO
after 30 years, they are now looking at grain boundary fixes to prevent spontaneous domain flipping which results in bulk demagnetization. The large loss of coercivity (seen as the green-to-red shift of the hysteresis curves above) is a problem for manufacturing.
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My thoughts:
This is a real magnet, not a meteor. It holds real promise. Properties are promising.
Should Lynas be concerned? Should investors be worried?
No and No, imho based on math and logic.
Why not? Because even if they commercialize a magnet that combines the strengths of SmCo and NdFeB, the crustal abundance of Bismuth (akin to Pd, just 2X gold/platinum) would result in a very small market (the magnets are 50% bismuth by stoichiometry and closer to 75% by weight). It is one of the rarest of all metals.
So why do they bother? Same reason the meteor gets a look: human beings, especially those who seek to be scientists, are an extremely curious lot. And there might be a breakthrough that could lead to commercial value. Any new magnet is of great interest.
But the use of bismuth means it can never be a competitor to neodymium PM. Nd is ~5000X as abundant as Bi.
I am convinced that there will never be a more commercially valuable magnet market than NdFeB.
So are the Chinese.
(20min delay)