Permanent magnets-Neodymium Disc Magnet are certain bodies that continuously generate a magnetic field without the need for an external source such as an electric current flow. This has the advantage that the magnetic field is constant and that no additional element is required to produce it, as is the case with electromagnets.
However, the magnetic force cannot be controlled as with the latter, or it can even be completely disconnected for a certain period of time, and then specifically reactivate the magnetic field. Hence the name of permanent magnets, because they are permanently magnetic.
What types of permanent magnets are there?
Permanent magnets differ in their basic materials. There are generally two different types:
Permanent ceramic magnets.
Permanent metallic magnets.
When we speak of a permanent ceramic magnet, it is made of ferrite. Metals can be a mixture of samarium and cobalt, aluminum, nickel and cobalt (Alnico) or neodymium, iron and Bohr. If you already know which properties are important for the intended use before manufacturing the magnet, you can adapt the combination of these elements accordingly. The shape of the permanent magnets can also be adjusted individually. The magnetization itself takes place at the end.
What types of permanent magnets are there
In this context, we also need to clarify the terms “isotropic” and “anisotropic”. This is the meaning of magnetization. Substances are called isotropics if they can be magnetized in any direction. They are anisotropic if there is only one direction, called the preferred address, in which the material can be magnetized. Anisotropic substances generally have higher magnetic values than isotropic substances.
What are the differences between the different materials of permanent magnets?
Neodymium: This material offers a high energy density and is extremely resistant to demagnetization. However, it is a material sensitive to oxidation, so they are not suitable for use outdoors or in humid environments.
Samarium: Magnets made of this material have an energy density similar to neodymium magnets, but can be used without any additional protective coating when exposed to moisture. They are also resistant to high temperatures.
Ferrite: This magnetic material is often used because it is the cheapest. If a particularly strong magnetic force is not required, they are used in a wide variety of fields. No less important because, although very cheap, they remain relatively insensitive to temperature and resistant to demagnetization.
Alnico: Alnico magnets are probably the oldest Sm2Co17 Magnet on the market. Although they can be easily demagnetized, they can withstand temperatures up to 550 ° C.