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Magnets are much more than simple fridge decorations. They serve us in our everyday life, through their use in loudspeakers, toys or engine constructions. Where else we can find magnets and what kinds of them we can distinguish, we will find out more in this article.
When we talk about magnets, electromagnets definitely deserve a special place due to their specific operation. They are the source of a magnetic field only when a current flows through their core, which leads to another issue – how are electromagnets constructed?
The construction of an electromagnet is relatively simple. It usually consists of a coil wound on a core of ferromagnetic material (such as iron, cobalt or nickel). The number of turns and the amount of current depends on how strong a magnetic field is produced by the electromagnet. The more coils and the higher the height of the current, the stronger the magnetic field.
Industrial electromagnets are used in the construction of electric machines and electromagnetic cranes, but this is not the only application for this unique invention. You meet a holding elect romagnet every day and it is possible that you do not even realize it. It is found in doors where card readers, code keypads, etc. are installed. On the other hand, in electric bells that you will find in schools, it is the electromagnet that attracts the hammer to the bell. On the other hand, in scrap yards it is used for moving heavy iron elements.
Permanent magnets are simple elements which produce a permanent magnetic field. They are divided into several types depending on their properties and also because of the way they interact with electrical charges
These are the second strongest magnets, just after neodymium magnets. They are distinguished by their high resistance to demagnetization, however, their advantages do not end there. They are resistant to corrosion and in addition they can operate in the environment with the temperature as high as 300°C. These features make them most commonly used in the automotive, medical, and aerospace industries, e.g. in implants, prostheses, couplings, and engines.
They are created by connecting iron, boron and neodymium, thanks to the method of powder metallurgy. This means that all magnet components are pressed in a magnetic field at an elevated temperature. These are the strongest magnets and they are also extremely resistant to corrosion. However, it is worth to know that due to their construction they are particularly vulnerable to damage. They are used in electrical devices, such as loudspeakers, alarms or microphones, in toys or in construction of engines and generators.
Ferrite magnets are made using iron and barium or strontium. They are resistant to salts, acids, gases, corrosion and grease, but due to their construction they are relatively fragile and brittle. However, they are characterized by reasonable price, that is why they are often used in production of holders and separators, as well as in electronics.
The main advantage of Alnico magnets is undoubtedly their resistance to really high temperatures – they can withstand up to 500°C. Although they are made of aluminum, nickel and cobalt compounds, they are less brittle than neodymium and ferrite magnets. They also have high corrosion resistance, but it’s mainly their resistance to high temperatures that makes them used in devices such as microwave ovens and sensors.