How cool! There are several things I'm looking after now
How cool! There are several things I'm looking after now
Wanted list:
Ubris
Fantastic collection of promotional materials, Jerome!
I want those BoB magnets.
You and several others.Originally Posted by Patrick
Yeah, that's the problem.
Do those magnets lose their magnetic-ness if they're not stuck to metal from time to time?
...Yeah, that's the problem.
Do those magnets lose their magnetic-ness if they're not stuck to metal from time to time?
Question
Do magnets ever lose their magnetism?
Asked by: Kevin H.
Answer
Yes, it is possible for a permanent magnet to lose its magnetism. There are three common ways for this to occur:
1) Via heat: ferromagnet materials will lose their magnetism if heated above a point known as the Curie temperature. At this point, the energy being put into the magnet from the heat will permanently disrupt the magnetic domain structure of the material, turning it into a paramagnetic material [a similar effect occurs in materials called hard ferrites, which exhibit a form of magnetism called ferrimagnetism; the analogous temperature for these materials is known as the Neel point]. You would have to re-magnetize the magnet again, either in a solenoid or with another permanent magnet, in order to restore the magnetism. If you heat a magnet up a little bit, it will lose some of its magnetism, but on returning to room temperature [depending on how high it was heated, and on the shape of the magnet itself], full magnetism can be restored.
2) Via a demagnetizing magnetic field: permanent magnets exhibit a characteristic called coercivity, which is the ability of a material to withstand being demagnetized by an applied magnetic field. Modern permanent magnet materials such as Sm-Co and Nd-Fe-B have high coercivities; older materials such as Alnico or ceramic [hard ferrite] materials have lower coercivities. With a strong enough magnetic field of opposite polarity, it is therefore possible to demagnetize the magnet [whether this comes from another permanent magnet, or a solenoid]. Interestingly, an opposing magnetic field is sometimes applied to a magnet in order to 'knock it down', or to lower its overall magnetic output, so that it can be used appropriately in an application.
3) Via shock: this really only applies to older materials such as magnetic steels and Alnico materials; the mechanism that creates coercivity means that they are susceptible to being demagnetized if enough energy is transmitted through the material via a shock, such as being dropped or hit with a hammer. Modern materials do not suffer this type of problem.
Answered by: Gareth Hatch, Ph.D., Director of Technology - Dexter Magnetic Technologies
"It's a little known fact that there are three ways for a permanent magnet to lose its magnetism..."
Thanks for the education.
Thank you Cliff.
That's classic!!!"It's a little known fact that there are three ways for a permanent magnet to lose its magnetism..."
Thanks for the education.
Promise me you'll always remember: You're braver than you believe, stronger than you seem and smarter than you think.
Oh My DAYS - what an amazing collection! an inspiration
That's the one with "Blue Air Compressor" in it! I like that hokey story!
John
Simply wonderful, Jerome!
sk
Nice! So what's in the Oct. '86 OMNI that makes it special?
"The End of the Whole Mess".
John
I thought it was weird they have no mention of King on the cover of the '86 Omni.
I think I'll try to look up who "Won a trip to outer space (honest!)".
Promo items sent to me by a very kind fellow member.
Nice promo items, Jerome.
Just going through files and found signed mini prints (~4'x7") that I believe were sold or distributed at Palavercon. I did not attend, but purchased these either in advance, or shortly after the event.
Lovely! The radish is great...
Great Collection, Jerome!!!!!!!
I especially admire the way you display the books. Very classy!!!!!
28 in 23 (?)!!!!
63 in '23!!!!!!!!!!
My Collection: https://www.thedarktower.org/palaver...ion-Merlin1958
The Houston Astros cheated Major League Baseball from 2017-18!!!! Is that how we teach our kids to play the game now?????
An amazing book collection and fantastic collection of promo material
My Stephen King collection
http://www.thedarktower.org/palaver/...on-Stockerlone
Non-King collection
http://www.thedarktower.org/palaver/...rlone-Non-King
I have always thought that Jerome have the nicest display for his collection, hands down!. Nice promo item as well.
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