Permanent Magnet Lifespan: Calculating Its Duration

  • Context: High School 
  • Thread starter Thread starter SciencePF
  • Start date Start date
  • Tags Tags
    Magnet Permanent magnet
Click For Summary
SUMMARY

The lifespan of permanent magnets, such as neodymium and magnetized iron bars, is influenced by factors like temperature, mechanical shock, and proximity to other magnets. While neodymium magnets can last several thousand years, magnetized iron bars may last around 300 years before losing their magnetic properties due to a process called "dissorientation." Permanent magnets can generate electricity indefinitely as long as they are moved near a wire, but their effectiveness diminishes over time due to external forces and environmental conditions. Overall, the degradation of magnetism is gradual, typically losing about one percentage point every ten years under stable conditions.

PREREQUISITES
  • Understanding of magnetic properties and materials, specifically neodymium and magnetized iron.
  • Familiarity with electromagnetic principles, including Lenz's Law.
  • Knowledge of factors affecting magnetism, such as temperature and mechanical stress.
  • Basic concepts of energy generation using permanent magnets in generators.
NEXT STEPS
  • Research the long-term stability of neodymium magnets under varying environmental conditions.
  • Explore the principles of Lenz's Law and its application in electricity generation.
  • Investigate the design and efficiency of the Bedini SSG motor and similar systems.
  • Study the effects of temperature and external magnetic fields on permanent magnet performance.
USEFUL FOR

Engineers, physicists, and hobbyists interested in magnet technology, energy generation, and the longevity of magnetic materials will benefit from this discussion.

SciencePF
Messages
55
Reaction score
0
Hello!
What is the lifetime of a permanent magnet? How we calculate it?
Thanks
 
Physics news on Phys.org
I think there is no formula to find such a lifetime for permanent magnets.
Magnets (i mean the normal one found in loud speakers, fridge doors, horse shoe) doesn't loss its magnetic property significantly over time. The factor that influence lifetime are: temperature, shock (& hitting), placing magnets such that north facing close to north of other magnet, etc.
But magnetic properties due to electron stays forever.
 
How far we can generate electricity from a rare Earth magnet(permanent)?
 
satya98 said:
How far we can generate electricity from a rare Earth magnet(permanent)?

Do you mean how much can we generate with a permanent magnet or how long for could we generate before it loses it's magnetism?
 
Indefinitely. The energy doesn't come from the magnet. It comes from whatever is pushing the magnet near a wire.
 
Antiphon said:
Indefinitely. The energy doesn't come from the magnet. It comes from whatever is pushing the magnet near a wire.

So the magnetism of a natural magnet never dies off? It doesn't have a life span?
 
From an earlier PF post of mine:

"In your context, magnetism, such as with a magnetized iron bar or neodymium(for example) composition DOES have a "lifespan"

A "magnetised" iron bar effects a "dissorientation" that is not "normal"
In time, the iron bar will re-orient into a non-magnetic, normal state.

Not sure about the figures, but I recall that it is somewhere around 300+ years for an "iron" magnet, and several thousand(perhaps 10's of thousands) for neodymium.
Again, I may have my figures wrong in exact detail, but nonetheless, YES... there is a "lifespan"

Source: https://www.physicsforums.com/archive/index.php/t-121135.html
 
pallidin said:
From an earlier PF post of mine:

"In your context, magnetism, such as with a magnetized iron bar or neodymium(for example) composition DOES have a "lifespan"

A "magnetised" iron bar effects a "dissorientation" that is not "normal"
In time, the iron bar will re-orient into a non-magnetic, normal state.

Not sure about the figures, but I recall that it is somewhere around 300+ years for an "iron" magnet, and several thousand(perhaps 10's of thousands) for neodymium.
Again, I may have my figures wrong in exact detail, but nonetheless, YES... there is a "lifespan"

Source: https://www.physicsforums.com/archive/index.php/t-121135.html

yes but you are referring to iron that has been magnetised and that's fair comment :)

but for naturally occurring magnetic iron or other rare Earth minerals its more likely to be indefinately

We can (in geology) measure paleomagnetisim in rocks ging back 10's and more of milions of years

Dave
 
Antiphon said:
Indefinitely. The energy doesn't come from the magnet. It comes from whatever is pushing the magnet near a wire.

I did'nt get u correctly. wat my question is how long the electricity can be generated from a permanent magnet.
For suppose I am generating electricity from a permanent magnet by shaking(lenz's law). How long I can generate electricity by this process if I shake it for a life time
 
  • #10
satya98 said:
How long I can generate electricity by this process if I shake it for a life time

For a lifetime.
 
  • #11
jarednjames said:
For a lifetime.

I am working on project regarding this concept. If , what we thought is true, then a generator of life time validity is going to be invented
 
  • #12
satya98 said:
I am working on project regarding this concept. If , what we thought is true, then a generator of life time validity is going to be invented

How is that?

Natural magnets are no where near as useful for power production as electromagnets. Far too weak.

You also still have the problem of bearings wearing out and other components failing. The magnets are only a small part of the overall system.

I get this twitch in my neck every now and then. I've found it's a good indicator of when a topic is about to hit the realms of perpetual motion machines. And here it comes again...
 
  • #13
I was actually wondering the same thing about rare Earth magnets, so thanks for posting this question. and it's not about perpetual motion :P looking into the validity of Bedini SSG motor to play with. don't care about perpetual motion, just interested in how much actual work you can get from that kind of a system, short of part failure. i read somewhere the opposing magnetic forces would "blow away" the magnetism of a magnet.
trying to verify if that is true or not.
(though i have to admit, it is pretty funny to read these kinds of posts and see everyone groan when there is a suggestion of perpetual motion, i can almost hear your headaches starting :P)
 
  • #14
I was actually wondering the same thing about rare Earth magnets, so thanks for posting this question. and it's not about perpetual motion :P looking into the validity of Bedini SSG motor to play with. don't care about perpetual motion, just interested in how much actual work you can get from that kind of a system, short of part failure. i read somewhere the opposing magnetic forces would "blow away" the magnetism of a magnet.
trying to verify if that is true or not.
(though i have to admit, it is pretty funny to read these kinds of posts and see everyone groan when there is a suggestion of perpetual motion, i can almost hear your headaches starting :P)
 
  • #15
I can't find a wiki page (or anything short of sites screaming crackpot) on this "Bedini SSG motor".

From the few items I have seen, it looks like a load of non-sense and some variation of a PMM. However, without something in detail on it I can't say one way or the other.
 
  • #16
From: http://www.eamagnetics.com/gen_faq.asp#How_long_will_a_permanent_magnet_last

How long will a permanent magnet last?

A permanent magnet will retain its magnetism unless it is affected by a strong outside magnetic or electrical force, or elevated temperatures. If they are not exposed to any of these conditions, permanent magnets will lose magnetism on their own, however this degradation is very slow, on the order of one percentage point every ten years or so.
 
  • #17
What, if anything, would cause a permanent magnet to lose its 'power' over time? Would it eventually be reduced to zero, even if only in theory?
 
  • #18
"...The length of "life" of a permanent magnet depends on many factors. When the domains are randomized again, the material will cease being magnetic, but this can be a very gradual process. This re-randomizing is affected by several things. The higher the temperature, the faster this process will happen..."

Source: http://education.jlab.org/qa/permmagnet_01.html
 
  • #19
If you intend to use it in a generator as it will be generating a current in the stata coils there will be a magnetic field formed in these that will oppose the field of your magnets. this will very very very slowly degrade the magnet, probably the Earth's magnetic field would have more of an effect.

All depends on the size of the stata coils and the strength of the magnet
 

Similar threads

High School Can we use a permanent magnet and a copper rod to create an electret?
  • · Replies 16 ·
Replies
16
Views
2K
High School Permanent magnets and energy question
  • · Replies 16 ·
Replies
16
Views
3K
High School Basic Straight Line Permanent Magnet Accelerator
  • · Replies 3 ·
Replies
3
Views
2K
Graduate PPMT, Magnetic Flux Switch, electro-permanent magnet generator
  • · Replies 8 ·
Replies
8
Views
4K
Undergrad Is this analogy between Magnetic Force and Gravitational Force accurate in helping to understand what contributes more to a stronger magnetic force?
  • · Replies 11 ·
Replies
11
Views
2K
High School Magnetic field coil ferrous material for loudspeaker
  • · Replies 31 ·
2
Replies
31
Views
5K
Undergrad Permanent Magnetic Dipole in an electromagnetic field
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Permanent magnet's magnetic field calculation
  • · Replies 23 ·
Replies
23
Views
5K
Undergrad How can there be neodymium magnets when neodymium is paramagnetic?
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad How Do Magnetic Forces Differ Between Magnets and Wires?
  • · Replies 1 ·
Replies
1
Views
2K