Magnet has a lot of magic functions.now, let us introduce it.
Magnet is an object that is related and attractive. Iron, Nickel, and cobalt composed magnet. the internal structure is arranged in the same direction, one north pole, and another south pole.
Iron,Nickel, cobalt has a difference in magnetic substances. the electrons inside can be aligned in the same spontaneous direction. then strengthened the magnetic to form a magnet.
The process of attracting iron by magnets attracts the iron blocks. the magnets and the iron blocks will stick together.we say that the magnet has magnets.that means the magnets can attract iron but not aluminum, copper , because different metal’s internal structure is the difference.
Magnets have a permanent magnet and non-permanent magnet. Permanent magnets can have permanent magnetic for a long period of time without being easily demagnetized as a natural product. But non-permanent magnets need in some conditions to appear magnetic, such as electromagnets.
Development history of magnets:
5000 years ago Humans discovered natural magnetite
2300 years ago Chinese grinded a natural magnet into a spoon shape and placed it on smooth ground. with geomagnetism, the spoon handle guide was the first guide instrument in the world.
1000 years ago Chinese use iron and magnetic rod magnetize, to make the world’s first compass
The 1100 year Chinese use magnetic needle and an azimuth dial to make a magnetic compass for maritime
In 1829, Danish physicists discovered that current-induced magnetism.
In 1930, Japan discovered a new kind of magnets that mixed elements of nickel, aluminum, and cobalt.
In 1970,Japan scientists invented the neodymium magnet. this magnet is called permanent magnets.
Now,neodymium magnet is the strongest magnet in the world.neodymium magnet can absorb 640 times itself weight. because the steady high performance and hardness, then widely used in electronic products,such as disks, mobile phones, headphones, toys, packages…
But neodymium magnet uses sintered technology.the material contacts ndfeb and iron,if you don’t plate,it will easy to get rust.
When we use the magnet, we will found that the magnetic stronger, the more fragile.that’s because when magnet produces,use power sintering. The sintering time is long, the inside of the magnet is lacked flexibility.
Under a strong magnetic field, magnet attached and repelled, which will offer magnet a large reaction force.when hit other hard objects,it will easily be broken. When the magnet is fragile, each fragile magnet also has s pole and N pole, that’s the pole always show in pairs. the fragment can’t separate N pole from S pole. each magnet has its own pole, no matter how small it is.
