https://www.physicsforums.com/showpost.php?p=1195930&postcount=5'Wear' is a somewhat misleading term. Permanent magnets gradually decrease in strength, but this has very little to do with usage. The "life" of a permanent magnet depends on many factors. Naturally occurring forces conspire to knock the little domains out of alignment. But this is normally a very slow process. Temperature is a major player in this process. The higher the temperature, the faster this process will occur. Extreme heat [surpassing the curie point] will immediately randomize the domains. A sharp blow can also knock domains out of alignments, as can other nearby magnetic or electrical fields. Radiation can also knock domains out of alignment. But again, under normal conditions, neither your fridge or you will live long enough to watch the little fellow fall to the floor in exhaustion. At the quantum leve [e.g., electrons] magnetism is eternal.
linux kid said:Under what conditions will a permanent magnet loose it's magnetic force:
1: I have read that the magnet will lose some energy when it "hits" the metal item. Is this the only way it will lose it's energy?
2: Will it degrade by simply sitting?
linux kid said:What does "domain" mean here?
Also, when you say heat, is there a certain threshold or referencepoint? For example does room temperature count or are we talking higher temps?
linux kid said:Does a permanent magnet ever loose it's energy or decrease over time? I read somewhere that a "fixed" magnet's energy will dissipate in time as it does work. I don't know what they mean by fixed.
Also, will a permanent magnet work without the Earth's energy (eg. in space).
hover said:A permanent magnet looses energy very slowly over time. Thats the point though, its supose to keep its magnetic field
If none of these external factors are present, then there isn't any reason for the domains to get realigned.Even without the external aspects that ranger listed above?
Yes.Does all this mean that as long as the domains stay in their origional position the magnet will not be affected?
linux kid said:Oh, I have one more :):
Do permanent magnets rely on the Earth (will they work in space)?
Permanent magnets are objects that create a magnetic field without the need for an external electric current. They have a north and south pole and are made from materials such as iron, nickel, and cobalt.
Permanent magnets work by aligning the magnetic domains within their material in the same direction, creating a strong magnetic field. This field can attract or repel other magnets, as well as attract certain metals.
Permanent magnets have numerous uses, including in electric motors, generators, speakers, and hard drives. They are also used in magnetic compasses and as closures for bags and jewelry.
Yes, permanent magnets can lose their magnetism over time, especially if exposed to high temperatures or strong external magnetic fields. However, some materials, such as neodymium, are more resistant to demagnetization.
There are several ways to demagnetize a permanent magnet, including heating it above its Curie temperature, hammering or dropping it, or exposing it to a strong external magnetic field in the opposite direction. However, these methods may not work for all types of permanent magnets.