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General knowledge about magnets
May 11, 2018

General knowledge about magnets


With the development of society, the application of magnets has become more and more widespread. From high-tech products to simple packaging magnets, NdFeB magnets and ferrite magnets are currently widely used. There are many kinds of magnets. Generally divided into two categories of permanent magnet and soft magnetic. What we call magnets generally refer to permanent magnets. A magnet is an object or material that generates a magnetic field. It is usually made of a metal alloy and has a strong magnetic property. Traditionally, it can be divided into "sexual magnets" and "non-sexual magnets."

Magnets can be natural products, also known as natural magnets, or they can be made by hand (strong magnets are neodymium-iron-boron magnets). Non-magnetism will abruptly lose magnetism when it is heated to a certain temperature. This is due to the arrangement of numerous “elemental magnets” that make up the magnets from order to disorder; magnets that lose magnetism are placed in a magnetic field when the magnetization reaches At a certain value, it is magnetized again, and the arrangement of "meta-magnets" goes from disorder to order.

Basic knowledge

The ancient Greeks and Chinese found natural magnetized stones in nature, calling them "magnets." This kind of stone can magically suck up small pieces of iron and always point in the same direction after swinging freely. Early sailors used this magnet as their early compass to identify directions at sea.

After thousands of years of development, magnets have become a powerful material in our lives today. By synthesizing alloys of different materials, the same effect as the magnets can be achieved, and the magnetic force can also be increased. Artificial magnets appeared in the 18th century, but the process of making stronger magnetic materials was slow until Alnico was manufactured in the 1920s. Subsequently, Ferrite was manufactured in the 1950s and rare earth magnets (Rare Earth magnets include NdFeB and SmCo) in the 1970s. At this point, magnetic science and technology have been rapidly developed, and ferromagnetic materials have also made the components more compact.

Magnetization (orientation) direction

Most magnetic materials can be magnetized to saturation in the same direction. This direction is called "magnetization direction" (orientation direction). Magnets that are not oriented (also known as isotropic magnets) are much less magnetic than oriented magnet separators (also called anisotropic magnets).