Ferrite magnets also called black magnets are made of iron oxide and barium or strontium ferrite. Ferrite magnets are highly resistant to corrosion and adverse external factors; so they do not need any type of coating.
To obtain ferrite magnets or ceramic magnets we have a production process more specifically for molding, we can find different shapes of ferrite magnets depending on the need. Since it is not the same to use it for a car engine than for a magnetic closure.
Ferrite magnets are multifunctional permanent magnet, that is, it has a wide range of applications, so depending on it we are going to allocate find:
The first ferrite to be used was magnetite which was used for compasses. It was not until the end of the 19th century that the components which form the alloy of the ferrite magnet became established. Ferrite magnets can also be called ceramic magnets, due to their visual appearance being a dark gray metallic oxide resembling porcelain.
Depending on the coercivity of the ferrite we can find:
Hard Ferrite Magnets: Hard ferrite magnets are those with high coercivity, so they are not easy to demagnetize. Hard ferrite magnets are composed of iron, cobalt, barium, and strontium → these are used for speakers and microwaves among others.
Soft ferrite magnets: Hard ferrite magnets are those with low coercivity, unlike hard ferrite magnets, which are easier to demagnetize. Soft ferrite is composed of a mixture of iron and light metals (nickel, aluminum, or manganese) → these are intended for electrical transformers.
When working with anisotropic qualities, an alignment of the particles is made in a single direction, obtaining magnetic characteristics. In addition to being anisotropic, they can also be isotropic, unlike anisotropic, the clamping ferrite magnet strength is lower.
Large ceramic magnets have high hardness and high brittleness. In addition, with these magnets, you can work from -40ºC to 250ºC. Ferrite magnetic permeability is so high, which means that this type of permanent magnet, like others with high magnetic permeability, has a great power of attraction.
Black magnets are the cheapest on the market. Ferrite magnets have a high corrosion resistance and, therefore, are one of the most appropriate products for different outdoor uses thanks to being stainless. They are probably the best alternative to neodymium magnets since they are not only resistant to moisture and corrosion but also resistant to different types of chemicals.
IMA | Grado | Nomenclatura | Remanencia | Fuerza Coercitividad | Coercitividad Intrínsica | Energía Máxima Producto | Temperatura de Trabajo | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
![]() | Grade | Nomenclature | Remanence | #colspan# | Coercive force | #colspan# | Intrinsic coercive | #colspan# | Maxium energy product | #colspan# | Working temp | ||||
Ferrite Magnets | Grade | Nomenclature | Br | #colspan# | Fuerza bHc | #colspan# | Fuerza Ihc | #colspan# | (BH) max | #colspan# | Working temp | ||||
Ferrite Magnets | Grade | Nomenclature | Br max (T) | Br min (T) | HcB min (kA/m) | HcB max (kA/m) | HcJ min (kA/m) | HcJ max (kA/m) | BHmax min (kJ/m³) | BHmax max (kJ/m³) | Max. Temp. trabajo: (ºC) | ||||
HF 7/21 isotropic | Y10T | HF 7/21 | 0,20 | 0,22 | 125 | 145 | 210 | 250 | 6,5 | 8,0 | 250 | ||||
HF 26/20 anistropic | Y30 | HF 26/20 | 0,38 | 0,39 | 191 | 210 | 199 | 220 | 26,0 | 28,0 | 250 | ||||
HF 27/23 anistropic | Y30BH | HF 27/23 | 0,38 | 0,39 | 223 | 235 | 231 | 245 | 27,0 | 30,0 | 250 |
By having high corrosion resistance, we can use ferrite magnets for outdoor applications and in places where there is a lot of humidity.
Depending on the type of ferrite magnet, we can use it for one application or another. In other words, an application for use with a reduced space is not the same as an application with a larger space. On the other hand, depending on whether it is a soft ferrite magnet or a hard ferrite magnet, we will use it for one application or another.
The black magnets are quality components. In addition, they are the cheapest magnets in the group of permanent magnets, which is why they have different applications, the most important of which are:
Ferrite magnets need to follow a series of steps to ensure quality, which is why we will explain them in detail below: