Magnet, in our childhood memory deep, it is a magical thing.
Magnet war play in the classroom, class two magnetic warriors each take a magnet, on both sides of Central Line in place at the same time, such as the referee gave both sides at the same time to let go of crossing magnet loses will be taken away, is playing.
Can see Tom cat is on the cartoon Tom and jerry jerry mouse USES the magnet so miserably.
▼ grew up without it, we know the life by the maglev train, the hospital of nuclear magnetic resonance (NMR), speakers, military electromagnetic gun rushed to research and development of future weapons, countries magnets have so many small make up together with everybody know about the magical function.
Usually we know the magnet is an object with mutually exclusive and attract each other.
Magnet is made of iron, nickel, cobalt, itself has a magnetic from internal structure to line up with the same direction, one end of the arctic,
At one end (at the South Pole
So there are many objects in the nature why no magnetic?
Iron, nickel, cobalt in the magnetic material is different, the arrangement of its internal electronic can spontaneously in the same direction, make the magnetic strengthen a magnet.
Magnet iron absorption process of iron to produce attractive, magnets and iron 'stick' together, we said magnet has a magnetic, which is a magnet to absorb iron to aluminum, copper objects, such as the internal structure of different metal is not the same.
Magnetic induction intensity unit is tesla, referred to as ',
▼ magnet is divided into a permanent magnet and the permanent magnets, magnetic properties and not easy loss of permanent magnet is long-term magnetic natural products, such as magnetite.
Non permanent magnetic magnet needs certain conditions to appear, such as the electromagnet.
▼ magnet development: 5000 years ago human discovered the natural magnet.
2300 years ago the Chinese natural grinding magnet into ladle, put on a smooth surface, under the action of magnetic, spoon handle guide, for the world's first guide apparatus.
1000 years ago, the Chinese people with iron bars and friction magnet magnetized, produced the world's first compass.
Around 1100 Chinese use magnet needle and bearing plate together, make the magnet type guide device, used for navigation.
In 1820, the Danish physicist found current induced magnetic.
Japan 30 s found nickel, aluminum, cobalt mixed elements of the new magnet.
In the 70 s, Japanese scientists invented the neodymium magnets, this new magnet is known as the 'king of the permanent magnet'.
Manufacturing process of permanent magnets are cast to make need magnets in the shape of sand mold, can cast magnets, materials including copper, cobalt, sulfur, nickel, iron, aluminum and titanium.
Metal into the electromagnetism stove, heated to 1600 ℃ above, all metals are melted into liquid.
▼ pour the solution into sand mold, the mold then burn up because of hardening sand in flammable gases.
▼ pried open with a hammer casting mill, let air into the cast grinding inside cooling material, let gas burn out.
The metal from the sand block points out, after casting metal or ordinary iron, do not have any magnetic force.
▼ tied metal parts on the copper pipe, into a larger pipe, the copper pipe in the middle position, closely around the silicon with sand, with the concrete seal both ends on both ends of the copper tube.
▼ inside furnace heating after 700 ℃, with clamp fixed on both ends of the copper tube, low pressure high charge current, then take out the metal parts, this step has been to the slight magnetization of the metal, the correct direction of the magnetic field is established.
▼ the magnet effect through the magnetization machine and machine will through the current magnetic to let its produce magnetic metals.
Pass first, have high voltage on capacitor charge (after the alternating current (ac)
And then through a discharge coil resistance is very small.
Peak discharge when the current is very high, can reach tens of amperes.
Electromagnetic produce strong magnetic field can make the metal permanent magnetization.
▼ and people have questions about the magnet have radiation?
The earth is actually a big magnet, the human all the time because of the influence of magnetic field, the human body has a different degree of micro magnetic field, the weaker and stable magnetic field is beneficial to human body.
The magnet makes constant magnetic field, not let radiation, can only be called magnetic field.
▼ neodymium magnets is also called the ndfeb magnet is one of the strongest magnet magnetic, it can absorb 640 times the weight of their body weight, known as the most powerful magnet.
On the hardness of high performance stability is widely used in electronic products such as hard disks, mobile phones, headsets and other products.
Note neodymium magnets used sintering molding, and ordinary magnet is casting process, because so and neodymium iron is contained in the material surface is easy to rust, need to do some protective plating processing, this is one of its shortcomings.
▼ we are in the process of using the magnet will find that the stronger the magnetism is more fragile, this is caused by its physical properties.
Magnets used in the process of production of powder sintering, the sintering time is long, its internal is a death, a lack of flexibility.
Magnet attraction under strong magnetic field are repellent reaction, also can give the magnet itself when encounter other hard objects would be easy to broken.
Magnet broken after each small magnets still have S N pole, this is because any magnet pole always come in pairs, broken and can not separate it with its South Pole of the arctic, no matter how small has its own each magnet poles.
▼ to pull the military high-tech weapons, electromagnetic gun.
It is installed in the gun tube coil, develop a strong electromagnetic field in the gun tube after the power supply, make the projectile and accelerated motion, it launches out.
Speed of 11 km/SEC, the speed can make any target instantly destroyed, its shell is ordinary metal projectile, the construction cost is very cheap.
A: market magnet manufacturers, the pursuit of high quality magnets next article: on February 28, the domestic rare earth market prices to rise