Alnico types, magnet and wire vendor links

[DrStrangelove]

Alnico Alloy types
http://www.salvarsan.org/content/alnico.html
This table derives from the 0100-00 standards document
page 7 table II-1 but includes Alnico 4.


magnet vendors - ad hoc list of some US vendors
http://www.salvarsan.org/magnetics/index.html


wire vendors - another ad hoc list
http://www.salvarsan.org/magwire/index.html


Permanent Magnetic Materials standard specifications (1.4Meg)
http://www.mmgca.com/standards/IMA-0100-00.pdf


-drh

[Zhangliqun]

Thanks -- the chart at one of those sites was at the very least useful for me to point out to some folks that, no, it is not true that there is no such thing as Alnico 4 or that Alnico 4 is just weakened Alnico 5.

(Unless degaussing magically removes copper and cobalt and adds aluminum and nickel....)

[DrStrangelove]

Thanks -- the chart at one of those sites was at the very least useful for me to point out to some folks that, no, it is not true that there is no such thing as Alnico 4 or that Alnico 4 is just weakened Alnico 5.

(Unless degaussing magically removes copper and cobalt and adds aluminum and nickel....)

Don't take my word for it. That chart is a heavily editted transcription.
Go to page 25 in the MMPA 0100-00 doc for the actual mention of A4.

Even then, I had to dig out the alloy recipe elsewhere, probably Arnold Magnetics or similar.

-drh

[Zhangliqun]

Don't take my word for it. That chart is a heavily editted transcription.
Go to page 25 in the MMPA 0100-00 doc for the actual mention of A4.

Even then, I had to dig out the alloy recipe elsewhere, probably Arnold Magnetics or similar.

-drh

So the ratio of metals in that chart is wrong?

[DrStrangelove]

So the ratio of metals in that chart is wrong?

The MMPA 0100 chart has no ratios for Alnico 4.

I found them and put them in my chart at
http://www.salvarsan.org/content/alnico.html

The MMPA 0100 document, the first and last word on magnet standards,
is what magnet manufacturors use.

If you know how to specify alloys from the MMPA 0100, then
there is never any confusion when you order Alnico.

-drh
--

[Rob S]

I'm puzzled why the chart shows alnico 8 and alnico 9 to have exactly the same ratios of elements but wildly different characteristics.

Somebody put me out of my bafflement please.

[DrStrangelove]

I'm puzzled why the chart shows alnico 8 and alnico 9 to have exactly the same ratios of elements but wildly different characteristics.

Somebody put me out of my bafflement please.

As I read it, they differ in how the alloy casting cools and solidifies.

Some molds have a "chill plate" at one end so that the alloy
solidifies from the bottom up and has a crystalline alignment.

This alignment of alnico 'crystals' can be reinforced by cooling
in a magnetic field.

These alnicos are called 'anisotropic' since they _must_ be
magnetized in the direction of the crystal orientation for
best effect.

Think of it as analogous to annealed vs. tempered steel -- they
have the same bulk chemical composition but their fine structures
make one soft and the latter hard.

-drh
--

[Zhangliqun]

What does Alnico 9 sound like anyway?

[Possum]

casting

While it IS true that these types of alnicos are oriented during cool down in a magnetic field its not NECESSERY to do that, you will still get the same alloy casting but when charged the magnets will be weaker. In my PAF research Tim Shaw from Gibson said that some PAF magnets were non-oriented A5 and that they sound like A2 magnets. My magnet supplier told me yes this is possible, but they won't make it for you unless you order a minimum of 300 lbs which is a half load anyway. Not sure why Shaw the stuff sounds like A2 when the content is the same just the gauss is lower......

[Zhangliqun]

You can take a normal modern A5 and weaken it and it will sound closer to A2. Not surprised the old school non-oriented one would sound similar too.