
Toyota develops first neodymium-reduced, heat-resistant magnet for motors - philipkglass
http://www.greencarcongress.com/2018/02/20180220-nd.html
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philipkglass
The headline is about the reduced neodymium content but the most interesting
part of the development is good high-temperature performance without requiring
any terbium or dysprosium. Additions of those expensive, almost-exclusively-
China-produced rare earth elements have been how neodymium magnets are made
suitable for high-power, high-temperature applications in motors and
generators. Neodymium, cerium, and lanthanum are more common rare earth
elements that have more good mineral resources outside China.

Most wind turbines use electromagnets in their generators, plus gearing
systems. So-called "direct drive" turbines use high strength permanent magnets
and can have longer lifetimes since the gearbox is the fastest-degrading part
of conventional turbines. But turbines with permanent magnet generators have
been only a minority of the market, in part because affordable and assured
supplies of key heavy rare earth elements are not available outside China.
(Goldwind, the only wind turbine manufacturer presently with an all-direct-
drive lineup, is Chinese.) Powerful magnets with less need for rare materials
can improve wind turbines to charge EVs as well as motors to move them.

~~~
shaqbert
While innovation to substitute an expensive ingredient from a potentially
unreliable supplier is laudable, from a chemist/metallurgist point of view I
wish there was more innovation in mining and cleaning up the process of
getting rare earth in the first place. Every rare earth element increases
option value and the potential to make further progress.

The main reason rare earth are expensive is that they mining is done in
decades old tech fashion, and dirty as hell. China does not seem to mind as
much, as long as it is controlling a strategic resource. Finding higher
concentration deposits, and improving the process of extracting the rare
earths elements is something I wish to happen more of...

~~~
greendesk
I also hope for innovation in the mining business.

This also seems to be underserved niche for start-up companies. From miners
that I have talked with, this is a small-moving enterprise setup.

~~~
perilunar
The real innovation in mining is coming from companies like Planetary Resource
and Deep Space Industries.

~~~
Cthulhu_
Those are moonshot companies; if they work they'd have the potential to bring
in trillions worth of minerals from space, but before they get there they'll
probably require hundreds of billions of investment first. Plus they'd
destabilize the market.

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Hextinium
I am very curious how they create grains of the cerium and then coat them with
neodymium to then fuse them together. I theorize that they first alloy the
cerium and lanthanum together and then grind it to a correct particle size.
Then they negatively electrically charge the rare earth particles and bond
neodymium to it with vapor deposition but I don't know it that is possible at
that scale. They would then press the particles together and heat them up so
that they fuse but don't liquify. All of this looks very very cool I just have
no concept for how it would actually happen.

~~~
Hextinium
Never mind, I just found the answer to my own question but I find it
interesting none the less. So as the solution of the three metals cool if done
correctly the neodymium will come out of solution to form a mesh of neodymium
around the grains of cerium and lanthanum in a similar way that pearlite forms
from austinite and ferrite in steel. This will give them a "sponge" of
neodymium to conduct the magnetic field but have the cerium and lanthanum act
as filler.

To explain what I am talking about way better than I ever could, this video is
how heat treating steel will change it's properties and why different steels
act the way they do.
[https://youtu.be/6jQ4y0LK1kY](https://youtu.be/6jQ4y0LK1kY)

~~~
neltnerb
If memory serves, in standard Nd-B-Fe magnets the neodymium also concentrates
at the grain boundary in the same way. My guess is that the Ce/La is acting as
a stabilizer for the internal structure replacing Nd that would otherwise have
been stuck inside the crystallite.

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LeifCarrotson
Copper induction motors use no magnets at all. 20 years ago, the control
algorithms and power electronics required were prohibitive, but the tech now
seems fundamentally superior to permanent magnet motors.

Why are magnetic motors of such interest to Toyota?

~~~
raverbashing
For several reasons. One of them is that induction motors don't work as a
generator, their torque/speed curve is bad as well

And magnets instead of electromagnets allow you to have brushless motors. You
could go with a synchronous motor but I guess the efficiency is not very good

~~~
stevendhansen
You are incorrect. Induction machines are often used as generators. My
employer uses them almost exclusively in the generator configuration. The
Lorentz force is symmetric; in the generator mode of operation the magnetizing
flux vector leads the torque-producing current vector instead of lags, but the
physics still works the same.

The induction torque speed curve is also very performant even when compared to
PM machines so I don’t understand your criticism. Source: motor control
engineer.

~~~
raverbashing
I stand corrected about not being able to use induction motors as generators,
still

As per wikipedia

> An induction generator produces electrical power when its rotor is turned
> faster than the synchronous speed... An induction generator usually draws
> its excitation power from an electrical grid

Which is not what they want in a car

Also they do want good torque at zero speeds, while it can be done with
induction motors it's not ideal

~~~
smaddox
The Tesla roadster uses PM free induction motors:
[https://www.tesla.com/blog/induction-versus-dc-brushless-
mot...](https://www.tesla.com/blog/induction-versus-dc-brushless-motors)

According to the article, the torque limitations are only for a poorly
controlled drive current.

~~~
raverbashing
Good article. And I quote:

> Today, all the hybrids are powered by DC brushless drives, with no
> exceptions. The only notable uses of induction drives have been the General
> Motors EV-1; the AC Propulsion vehicles, including the tzero; and the Tesla
> Roadster.

> Induction machines are more difficult to control. The control laws are more
> complex and difficult to understand. Achieving stability over the entire
> torque-speed range and over temperature is more difficult with induction
> than with DC brushless. This means added development costs, but likely
> little or no recurring costs.

A _hybrid_ has different characteristics and requirements from the motor than
a purely electrical vehicle as well

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londons_explore
This looks like it might be Toyota telling investors "If global neodymium
prices skyrocket again, we'll have an edge over our competitors".

The actual heat resistance is only of marginal benefit for automotive uses,
where more cooling fins or a fan are usually better solutions.

~~~
Iv
It is probably even more drastic than that: a few years ago China blocked
export of some rare earths to Japan for a few months.

This has led to several researchs aimed at reducing the strategical needs of
these minerals in the Japanese industry.

~~~
adventured
That's exactly what it is:

"Toyota is trying to make electrified vehicles less dependent on Chinese
minerals"

[https://www.cnbc.com/2018/02/20/toyota-is-trying-to-make-
ele...](https://www.cnbc.com/2018/02/20/toyota-is-trying-to-make-electric-
vehicles-less-dependent-on-chinese-minerals.html)

[https://www.bloomberg.com/news/articles/2018-02-20/toyota-
re...](https://www.bloomberg.com/news/articles/2018-02-20/toyota-readies-
cheaper-electric-motor-by-halving-rare-earth-use)

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donquichotte
How is this special?

I used to work at a company that makes pumps with magnetic bearings. To pump
hot liquids, we needed special magnets with higher Curie temperatures than
traditional Neodymium magnets. Our high-temperature products had Samarium-
Cobalt magnets and ran, if memory serves, up to almost 200°C.

~~~
philipkglass
There's a pretty good overview here:

[https://supermagnetman.com/blogs/news/understanding-
magnet-g...](https://supermagnetman.com/blogs/news/understanding-magnet-
grades-and-magnet-tables)

Neodymium-iron-boron magnets can have a higher energy product than samarium-
cobalt, but require additions of expensive/rare heavy rare earth elements to
work well at elevated temperatures. (Or require special microstructure
modifications like Toyota has developed.) SmCo magnets have had good high
temperature performance from the beginning, but a lower energy product.

Other issues that discourage widespread substitution of SmCo magnets for NIB:

\- Samarium is significantly rarer than neodymium in economically exploitable
rare earth resources (see table 1 here:
[https://pubs.usgs.gov/of/2013/1072/OFR2013-1072.pdf](https://pubs.usgs.gov/of/2013/1072/OFR2013-1072.pdf))

\- The iron-boron balance of a neodymium-iron-boron magnet is cheap, whereas
the cobalt in a SmCo magnet is relatively expensive.

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reacharavindh
Tried to read it on the phone. Got a huge blank page, with a few chat heads.
Wish people stick with basic HTML if they don't know what they're doing...

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acct1771
Are you sure the page loaded? What browser are you using?

The blog, and its linked Toyota page, both work well for me in the
Materialistic(HN reader) WebView.

~~~
reacharavindh
iOS 10, Safari, private mode

This is all I see..

[https://imgur.com/a/YdhZj](https://imgur.com/a/YdhZj)

