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Company News About magnet Date: 【2019-12-23】 / View: 【2578】Times
The composition of the magnet is iron, cobalt, nickel and other atoms. The internal structure of the atoms is relatively special, and they have magnetic moment. Magnet can produce magnetic field and has the characteristics of attracting ferromagnetic materials such as iron, nickel, cobalt and other metals.
Types of magnets: shape magnets: square magnets, tile magnets, irregular magnets, cylindrical magnets, ring magnets, disk magnets, magnet bar magnets, magnetic frame magnets, attribute magnets: samarium cobalt magnets, neodymium iron boron magnets (strong magnets), ferrite magnets, aluminum nickel cobalt magnets, iron chromium cobalt magnets, industry magnets: magnetic components, motor magnets, rubber magnets, plastic magnets, etc Class. Magnets are divided into permanent magnets and soft magnets. Permanent magnets are made by adding strong magnets to make the spin of magnetic materials and the angular momentum of electrons in a fixed direction. Soft magnets are made by adding electricity. (it's also a way to add magnetic force) when the current is removed, the soft iron will slowly lose its magnetism.
Hang the midpoint of the bar magnet with a thin line. When it is still, its two ends will point to the South and north of the earth respectively. The end pointing to the north is called the north pole or N pole, and the end pointing to the south is the guide pole or S pole.
If we think of the earth as a big magnet, the geomagnetic north pole of the earth refers to the south pole, and the geomagnetic South Pole refers to the North Pole. Between magnets, the poles of the same name repel and the poles of different names attract. Therefore, the compass repels the south pole, the north pole and the north pole, while the compass and the North Pole attract each other.
Classification: magnet can be divided into "permanent magnet" and "non permanent magnet". Permanent magnets can be natural products, also known as natural magnets, or manufactured manually. Non permanent magnets, such as electromagnets, appear only under certain conditions.
The magnet is not invented by man, it is a natural magnetite. Ancient Greeks and Chinese discovered that there was a kind of naturally magnetized stone in the nature, which was called "iron absorption stone". This kind of stone can magically suck up small pieces of iron, and it always points in the same direction after swinging at will. Early mariners used the magnet as their first compass to identify directions at sea. The first to discover and use magnets should be Chinese people, that is to say, making "compass" with magnets is one of China's four major inventions.
After thousands of years of development, today magnet has become a powerful material in our life. By synthesizing alloys of different materials, the same effect can be achieved as that of the magnet, and the magnetic force can also be increased. Artificial magnets appeared in the 18th century, but the process of making stronger magnetic materials was very slow until the production of alnico in the 1920s. Subsequently, ferrites were produced in the 1950s, and rare earth magnets (including NdFeB and SmCo) were produced in the 1970s. So far, the magnetic science and technology has been developed rapidly, and the strong magnetic materials also make the components more miniaturized.
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In 1822, French physicists Arago and lusack found that when electric current passes through a winding in which there is a piece of iron, it can make the iron in the winding magnetic
Magnetization. This is actually the first discovery of the principle of electromagnets. In 1823, sturgeon did a similar experiment: he wound 18 turns of bare copper wire on a U-shaped iron bar which was not a magnet bar. When the copper wire was connected with the voltaic battery, the copper wire on the U-shaped iron bar produced a dense magnetic field, which made the U-shaped iron bar become an "electromagnet". The magnetic energy of the electromagnet is more than twice as large as that of the permanent magnet. It can pick up the iron block that is 20 times heavier than it. When the power is cut off, the U-shaped iron bar can't hold any iron block and becomes a common iron bar again. Sturgeon's invention of electromagnet made people see a bright prospect of converting electric energy into magnetic energy. This invention soon spread in Britain, the United States and some coastal countries in Western Europe. In 1829, Henry, an American electrician, made some innovations in the sturgeon electromagnet device, replacing the bare copper wire with the insulated wire, so there was no need to worry about the short circuit caused by too close to the copper wire. Because the wires have insulating layer, they can be tightly wound together in a circle. The denser the coils are, the stronger the magnetic field will be, which greatly improves the ability to convert electric energy into magnetic energy. In 1831, Henry produced a new electromagnet. Although it was not big, it could hold a ton of iron. The invention of electromagnet has also greatly improved the power of generator.
Development course: 5000 years ago, human found the natural magnet (Fe3O4). 2300 years ago, Chinese people ground the natural magnet into a spoon shape and put it on a smooth plane. Under the effect of geomagnetism, the spoon handle guide, called "Sinan", is the first guide instrument in the world.
1000 years ago, Chinese people made the world's first compass by friction and magnetization of magnets and iron needles.
Around 1100, China combined the magnetic needle with the azimuth plate to become a magnetic guiding instrument for navigation.
From 1405 to 1432, Zheng He began his great pioneering work of navigation in the history of mankind with his guiding instrument.
1488-1521 Columbus, gamma, and Magellan used the compass to make the world-famous voyage discovery.
William Gibb, an Englishman, published a monograph "magnet" on magnetism, which developed the understanding and experiment of magnetism by ancient Greeks such as Thales and Aristotle.
In 1785, French physicist C. Coulomb established "Coulomb's law" to describe the force between electric charge and magnetic pole by torsion.
1820 the Danish physicist H.C. Oster discovered that current induced magnetism.
1831 British physicist M. Faraday discovered the phenomenon of electromagnetic induction.
1873 British physicist J.C. Maxwell completed the unified electromagnetic theory in his monograph "on electricity and magnetism"
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