Talk:Neodymium magnet

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Both KJ and Gaussboys give "grades" for their magnets (N38, N42, N45 etc.), but don't explain what exactly these mean, other than that higher grades mean stronger magnets. Can anyone shed light on that? Does it have to do with the purity of the material used to build the magnet?

I think this should definitely be covered in the article. -- Schnee (cheeks clone) 22:10, 22 Jun 2005 (UTC)

The typically listed "grade" of a magnet usually refers to the Maximum Energy Product or BHmax. In c.g.s. the units are in Mega-Gauss*Oersted, (MGOe) and they are more internationally known in S.I. units as Joules per cubic meter (J/m^3).

The "N, ND, or NS" prefix usually means Neodymium Iron Boron magnet alloy and the "Grade/number value" suggests that the alloy has a Maximum Energy Product of 38 MGOe. This magnetic characteristic is volume independent and only gives you an idea of what the net magnetic field of a magnet with a particular geometry will be.

The "grade" or Maximum Energy Product is usually not used in an calculations beyond first order and it is really not important in designing with strait line materials. Strait line magnet alloys have a strait normal curve in the II quaddrant their Hysterisis curve at moderate temperatures. The "grade" does help compare similar magnet alloys. This convention is also used in Samarium Cobalt alloys, but these usually start with a "S" or "SC".

Most Neodymium Iron Boron manufacturers allow a tolerance of ±10% on the Maximum Energy Product and this is specified in the MMPA/IMA magnet stanadrds. The International Magnet Association (IMA) is the old Magnetic Materials Producers Association (MMPA)and they have adopted the MMPA standards and definitions.

Usually a higher grade is stronger, but one vendor's strong N38 may be another vendor's weak N40. The grade impact will be transparent to most general purpose users, but industrial users should review the other three primary magnetic characteristics of a permanent magnet; Residual Induction (Br), Coercive Force (Hc) and the Intrinsic Coercive force (Hci). 72.240.22.233 00:13, 20 March 2006 (UTC)

It seems to me that the paragraphs in the "Caution" section should rightfully be reversed. Some people may disagree, but flesh wounds are for the most part worse than equipment damage. And these things can really pinch let me assure you. (71.233.165.69 00:36, 19 May 2006 (UTC))

• They can do a lot more than just pinch. Larger ones at higher grades are strong enough to attract things from even across a room at high speed. Make sure all your tool boxes and any loose metallic items are secured when moving one.

If somebody is wondering how to expand this article, a section about how those magnet are created would be great! :-) Peter S. 00:58, 15 June 2006 (UTC)

Yeah, I agree. How are Neodymium magnets made?!? ^_^ Jumping cheese ^Contact 08:54, 29 October 2006 (UTC)

[edit] Aspirin?

The article mentions toys containing neodymium magnets the size and shape of aspirin tablets. Can someone please replace this with a proper measurement? Even the original Bayer Aspirin is available in different shapes and sizes, let alone all the different stuff called "Aspirin" which is available in the USA. --BjKa 13:52, 8 November 2006 (UTC)

The size of one of these magnets is 2-4 millimeters in diameter and the same high.

[edit] Serious error in the Caution section?

The caution section states that neodymium magnets are not strong enough to pull a paperclip through a hand. I imagine as this is in the "Caution" section, that the intended meaning is that they are able to do that? Then, it should urgently be corrected. —The preceding unsigned comment was added by 82.139.254.221 (talk • contribs).

No - I don't think any consumer neodymium magnet could come close to pulling a paperclip through a hand. I have two 1" cube neodymium magnets and while they can create an uncomfortable pressure when placed above and below a hand, I can't imagine any magnet available to the public pulling an object through a hand. -SCEhardT 22:37, 9 December 2006 (UTC)

They definitely can hold up items on another side of your hand. They could not literally pull the item through the hand causing a large cut by any means. Looking at the citation given ( http://youtube.com/watch?v=NKZgGTD0qic ) it has nothing to do with pulling paperclips or objects through hands and looking about I can find no episode that shows so. Aicchalmers 18:53, 30 March 2007 (UTC)