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history and application of magnets

history and application of magnets


in this article, China professional magnet product factory, Zhongke will walk you through the history and application of magnets. Sourcing for wholesale magnets? Welcome to contact Zhongke and get sample.  

According to statistics, every car's manufacturing entails 17 magnets, luxury car of each will take more than 70 pieces of permanent magnet, car with permanent magnet about worldwide in 1997-160000 tons, by 2020 will increase to 240000 t, the air pollution situation, the current world "seven big car companies, including general motors (GM), ford (Fort), Chrysler Chryster) company, ToyoTa (ToyoTa), Honda (Honda), Mazda and nissan (Tsan) have the electric car production line, i.e., the powerful magnets in the field of car consumption.

In 1998, few electric cars entered the market. It is estimated that the ND-FE-B series of permanent magnet materials for permanent magnet motors of every electric vehicle will be about 3~ Skg. From 2005 to 2010, the demand of ND-FE-B series of permanent magnet materials for permanent magnet motors of electric vehicles reached 1080T and 4200t respectively. In addition, the developing electric motorcycles and electric bicycles also need a considerable amount of ND-FE-B permanent magnet materials.


Basic knowledge of magnets

Magnet is not invented by man, there is a natural magnetite, the earliest discovery and use of magnets should be from the Chinese. So the compass is one of the four great inventions of the Chinese. As for the composition that are iron, cobalt, nickel and so on, the atoms themselves have magnetic moments. Magnetic regions interact with each other so that they don't show magnetism..

However, under the guidance of external forces (such as magnetic field), the molecules tend to align in the same direction. It shows magnetism, which is commonly known as a magnet.

Iron cobalt nickel is the most commonly used permanent magnets and magnetic materials basically magnet & soft iron permanent magnet are strong magnetic combined to make the spin of magnetic materials and electronic angular momentum into fixed direction soft magnetic is combined with current (is also a kind of combined with magnetic method) and other current remove soft iron will slowly lose magnetism as to who discovered the earliest magnet is one of the oldest recorded the Chinese war human-god, so known as one of the four great inventions of China! China knew about the polarization of magnets in the first century BC. In the Warring States Period, a natural magnet was put on a graduated copper plate for divination. 

In the Northern Song Dynasty, two methods were used to make artificial magnets. One was to place the red-hot iron needle in the north and south direction, and then magnetize the iron needle with the magnetic field of the earth after it was cooled rapidly. The other is made by rubbing a magnet against an iron needle. The existence of magnetic declination is recorded in Mengxi Penyan, and it is found that under the influence of magnetic declination, the magnetic needle points to the south, slightly to the east than the real South.

Based on this knowledge, the scientific application of the magnet as a compass was developed. Magnet is just a general term, refers to the magnetic things, the actual composition does not necessarily contain iron. Relatively pure metallic state no permanent magnetic iron itself, only close to the permanent magnets can produce magnetic induction, general permanent magnet inside other impurity elements (such as carbon) was added to make magnetic stabilized, but it will reduce the electronic freedom and less prone to conduct electricity, so the current through the bulb light up.

Iron is a common magnetic element, but many other elements have stronger magnetic properties, such as rubidium, iron and boron compounds that are used in many strong magnets. The ancient Greeks and Chinese discovered a naturally magnetized rock in nature and called it "magnet". The stone magically sucks up small pieces of iron and always points in the same direction as it swings around. Early navigators used this magnet as their first compass to find their way around the sea. After thousands of years of development, today the magnet has become a strong material in our life.

By synthesizing alloys of different materials, the same effect can be achieved as the magnet, and the magnetic force can also be increased. Artificial magnets had been around since the 18th century, but the process of making more powerful magnetic materials was slow until the creation of Alnico in the 1920s. This was followed in the 1950s by Ferrite (Ferrite) and in the 1970s by Rare Earth magnet (including NdFeB and SmCo). At this point, magnetic science and technology has been developed rapidly, and strong magnetic materials also make the components more miniaturized.

magnet field discovery 

Discovery of magnetic Phenomenon of Ningbo strong magnet:

In the pre-Qin period, our ancestors had accumulated a lot of knowledge in this respect. In their search for iron ore, they often encountered magnetite, or magnetite (the main component is triferroxide).

These discoveries of magnets have been recorded for a long time. These findings are first recorded in several passages in the Guanzi: "Where there is a magnet on the mountain, there is gold and copper under it." Other ancient books such as the Classic of Mountains and Seas have similar records. The characteristics of magnetic iron absorption were discovered very early. "Lu Shi Chun Qiu" nine volumes of master there: "Ci zhao iron, or cited.

At that time, people called "magnetism" "kindness". They regarded the magnet's attraction to iron as that of a loving mother to her children, and thought: "stone is the mother of iron, but stone has kind and not kind, loving stone can attract his children, not kind stone can not attract."

Before the Han Dynasty, people wrote lomagnetism as a stone of kindness. If a magnet attracts iron, can it attract other metals?

Our ancestors made many attempts, and found that magnets did not attract either gold, silver, copper, or other metals, nor bricks or tiles. By the Time of the Western Han Dynasty, people had realized that a magnet could only attract iron, not other objects.

When two magnets are put together close to each other, sometimes they attract each other, sometimes they repel each other. It is now known that magnets have two poles, one N and one S. Like poles repel each other, opposite poles attract each other. People didn't know this at the time, but they were aware of it. In the Western Han Dynasty, an alchemist named Luan Da made use of this property to make two chess pieces. By adjusting the positions of the polarities of the two pieces, sometimes they attracted each other, sometimes they repented each other. Luan da called it "fighting chess."

He presented the novelty to Emperor Wudi of the Han Dynasty and demonstrated it on the spot. Emperor Wudi of the Han Dynasty was surprised, longxin great joy, actually sealed Luan Dawei "General five."

Luan Dali used magnets to create novel objects to deceive emperor Wu of the Han Dynasty. The Earth is also a large magnet, with its poles near the geographic South Pole and the geographic North Pole. Therefore, magnets on the earth's surface, when they can rotate freely, indicate north and South because they repel each other and attract each other.This was not clear to the ancients, but they were well aware of this phenomenon.

magnet application

Application of Strong magnet magnetic Phenomenon in Guangdong:

" Magnet Applications in Traditional Industries" :

In the description of the magnetic source of magnetic materials, electromagnetic induction, magnetic devices, we have mentioned some of the practical applications of magnetic materials.

In fact, magnetic materials have been widely used in various aspects of traditional industries.

For example, without magnetic materials, electrification would be impossible, because electricity is generated by generators, transmission by transformers, electrical machinery by motors, telephones, radios and televisions by speakers.

Magnetic steel coil structure is used in many instruments.

All of this has been said in the context of other things.

"Magnetic Applications in biology and medicine" :

Homing pigeon lovers know that if they are released hundreds of kilometers away, pigeons will automatically return home.

Why do pigeons have such a good sense of home?

Pigeons, it turns out, are sensitive to the earth's magnetic field and can use changes in the field to find their homes.

If a magnet is attached to the pigeon's head, the bird will get lost.

If pigeons fly over radio towers, powerful electromagnetic interference can also disorient them.

In medical science, nuclear magnetic resonance can be used to diagnose abnormal tissues and diagnose diseases. This is the familiar NUCLEAR magnetic resonance imaging technology. Its basic principle is as follows: the nucleus has positive electricity and carries out spin motion.

Normally, the arrangement of nuclear spin axes is irregular, but when placed in an external magnetic field, the nuclear spin spatial orientation transitions from disorder to order.

The magnetization vector of the spin system increases gradually from zero, and when the system reaches equilibrium, the magnetization reaches a stable value.

If the nuclear spin system is subjected to external action, such as radiofrequency excitation of the nucleus at a certain frequency, resonance effect can be induced.

After the radio frequency pulse stops, the activated nucleus of the spin system, unable to maintain this state, will return to the original arrangement state in the magnetic field, and at the same time, release weak energy, which becomes the radio signal. Many of these signals are detected and made to carry out spatial resolution, so as to obtain the distribution image of the nucleus in motion.

The characteristic of NMR is that flowing liquids do not produce signals known as flow effect or flow blank effect.

So the blood vessels are gray - white tubes, and the blood is black with no signal.

This allows the blood vessels to separate easily from the soft tissue.

The normal spinal cord is surrounded by cerebrospinal fluid (CSF), which is black and has a white dura set off by fat, making the spinal cord appear as a white strong signal structure.

Nuclear magnetic resonance has been used in imaging diagnosis of all systems of the whole body.

The best effect is the brain, and its spinal cord, heart large vessels, articular bone, soft tissue and pelvic cavity.

For cardiovascular disease can not only observe the anatomical changes in the chamber, large blood vessels and valve, and can make ventricular analysis, qualitative and semi-quantitative diagnosis, can make multiple sectional drawing, high spatial resolution, a heart and lesions, and its relationship with surrounding structures, superior to other X-ray imaging and two-dimensional echocardiography and nuclide and CT examination.

In the "Star Wars" program of the United States, there is a new weapon "electromagnetic weapon" development and research.

Traditional artillery uses the thrust generated by the instantaneous expansion of the explosion to accelerate the projectile and push it out of the barrel.

The electromagnetic gun, on the other hand, puts the shell in the solenoid and energizes the solenoid. Then the magnetic field generated by the solenoid will exert a huge force on the shell and shoot the shell out.

This is called an electromagnetic gun.

Similarly also has the electromagnetic missile and so on.

What is a maglev train?

Maglev is a high speed maglev train system with contactless electromagnetic levitation, guidance and drive systems.

It can reach speeds of over 500 kilometers per hour, the fastest in the world today.

Passenger transport vehicles have the advantages of fast speed, strong climbing ability, low energy consumption, low noise during operation, safety and comfort, no fuel, less pollution and so on.

And it is elevated and occupies very little arable land.

Maglev trains mean that these trains use magnetic fundamentals to float on rails instead of old steel wheels and track trains.

Maglev technology uses electromagnetic forces to lift entire train cars, freeing unwanted friction and unpleasant telephony to allow fast 'flight' with no contact and no fuel.

What is the magnetization (orientation) direction?

Most magnetic materials can be magnetized to saturation in the same direction, which is called the direction of magnetization (orientation).

Non-oriented magnets (also called isotropic magnets) are much less magnetic than oriented magnets (also known as anisotropic magnets).

More info about magnet, welcome to contact Zhongke magnet company.

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