The Naked Scientists

The Naked Scientists Forum

Author Topic: Do Magnets Wear Out ?  (Read 20406 times)

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Do Magnets Wear Out ?
« on: 16/09/2012 14:17:30 »
Dearest Magnetologists,

As a sheepy I of course luff magnets !.....from the moment I open my eyes to the time I go to bed they monopolise my every waking moment. Out of all the things surrounded by a magnetic field 'magnets' are right up there as my all time fave.

Look here are some that I have sexed up with snazzy special FX !



Magnets Sexed Up With Special FX Just Moments Ago.


Nice eh ?

What I would like to know is ...do magnets lose their magnetism over time ?...do they  just wear out ?  As a firm believer in empirical  study I am going to keep an eye on my magnets and will report here any appreciable loss of magnetism !...

Perhaps in the mean time ewe can indicate how long I'm likely to be observing my magnets ?..a few days ?...maybe as long as a few weeks ..lol...yes...as if !!


ta



neil
Ewe're Attractive
xxxxxxxxxxxxxxx


 

Offline evan_au

  • Neilep Level Member
  • ******
  • Posts: 4123
  • Thanked: 245 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #1 on: 18/09/2012 12:14:16 »
Strong permanent magnets are made of a "hard" magnetic material, which is initially magnetised in a strong magnetic field. This treatment takes the magnetic material away from it's lowest energy state. These magnets will demagnetise slowly over time as they return to their lowest energy state (or immediately, if they are heated above their Curie Temperature).
http://en.wikipedia.org/wiki/Neodymium_magnet#Magnetic_properties

http://www.ehow.com/how-does_5166377_magnet-lose-its-magnetism.html suggests that some types of magnets might lose 1% of their magnetism per decade.

Magnetite is sometimes found as a "Natural" magnet, but this mineral is mostly not magnetic; some suggest it is made magnetic by a nearby lightning bolt  http://en.wikipedia.org/wiki/Lodestone
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #2 on: 19/09/2012 10:37:42 »
Strong permanent magnets are made of a "hard" magnetic material, which is initially magnetised in a strong magnetic field. This treatment takes the magnetic material away from it's lowest energy state. These magnets will demagnetise slowly over time as they return to their lowest energy state (or immediately, if they are heated above their Curie Temperature).
http://en.wikipedia.org/wiki/Neodymium_magnet#Magnetic_properties

http://www.ehow.com/how-does_5166377_magnet-lose-its-magnetism.html suggests that some types of magnets might lose 1% of their magnetism per decade.

Magnetite is sometimes found as a "Natural" magnet, but this mineral is mostly not magnetic; some suggest it is made magnetic by a nearby lightning bolt  http://en.wikipedia.org/wiki/Lodestone


Sweet !!... thank ewe evan_au really interesting !...I don't know what my magnets are made from....will need to find out now because I want to know !  :)
« Last Edit: 19/09/2012 10:39:43 by neilep »
 

Offline damocles

  • Hero Member
  • *****
  • Posts: 756
  • Thanked: 1 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #3 on: 21/09/2012 13:00:30 »
http://en.wikipedia.org/wiki/Neodymium_magnet

These magnets are a glassy ceramic material Nd2Fe14B. They are usually coated with an outer layer of another more robust ceramic, because the material is reputedly quite brittle. Cigar shaped magnets like those pictured can be found on sale in toyshops etc. here.
 

Offline neilep

  • Withdrawnmist
  • Naked Science Forum GOD!
  • *******
  • Posts: 20602
  • Thanked: 8 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #4 on: 21/09/2012 14:16:08 »
http://en.wikipedia.org/wiki/Neodymium_magnet

These magnets are a glassy ceramic material Nd2Fe14B. They are usually coated with an outer layer of another more robust ceramic, because the material is reputedly quite brittle. Cigar shaped magnets like those pictured can be found on sale in toyshops etc. here.

Yes..they are the ones... thank you very much Damocles...... they are pretty fun to play around for a while !
 

Offline CZARCAR

  • Hero Member
  • *****
  • Posts: 686
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #5 on: 22/09/2012 16:42:30 »
i thinx heat can demagnetize
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #6 on: 22/09/2012 17:30:31 »
NdFeB magnets are not generally glassy. They have a well defined crystal structure.
Also the material has a metalic electrical conductivity  I don't think you can call them ceramic.
It's difficult to tell for certain but I think Neil's magnets are magnetite or ferrite which is pretty much a ceramic.
http://en.wikipedia.org/wiki/Ferrite_(magnet)
 

Offline RD

  • Neilep Level Member
  • ******
  • Posts: 8132
  • Thanked: 53 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #7 on: 22/09/2012 17:51:38 »
... It's difficult to tell for certain but I think Neil's magnets are magnetite or ferrite which is pretty much a ceramic.
http://en.wikipedia.org/wiki/Ferrite_(magnet)


Quote
Awesome Iron Oxide (Fe203)
http://www.amazon.co.uk/Tobar-PowerBuzz-Magnets/dp/B00369T36E/ref=pd_sim_k_h_b_cs_1
 

Offline damocles

  • Hero Member
  • *****
  • Posts: 756
  • Thanked: 1 times
    • View Profile
Re: Do Magnets Wear Out ?
« Reply #8 on: 22/09/2012 23:12:49 »
I stand corrected!

A local outlet had these in a rack as "rare earth magnets" -- guess the trade descriptions police will be after him soon.
 

The Naked Scientists Forum

Re: Do Magnets Wear Out ?
« Reply #8 on: 22/09/2012 23:12:49 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums