Ferrite Magnet

  

Magnets can produce magnetic fields that enable them to attract certain metals from afar without touching them. Some magnets are produced naturally and some are man-made. Although there are many different types of magnets, the two most popular artificial magnets are ferrite magnets and rare earth neodymium magnets.

Ferrite magnets, also known as ceramic magnets are a type of permanent magnet and are made of the chemical compound ferrite, which consists of ceramic materials and iron oxide (Fe2O3), the chemical composition is SrO-6 (Fe2O3). Re: Ferrite magnet? I'm not sure I fully understand but all guitar pickup magnets - ceramic included - have ferrite (iron) in them. (I don't know of the Samarium Cobalt mags have iron or not but I suspect they do.) In a ceramic magnet, the ferrite (iron) is suspended in the ceramic mix. In Alnico magnets, iron is about 50% of the magnet. Ferrite Magnets FB Series Magnetic Characteristics Distribution Chart The magnetic properties and derating curves of the materials of the Ferrite Magnets FB Series can also be checked. AFFORDABLE ferrite magnets for biomagnetism nice kit to start or complete your collection. Goiz Active BiomaneticEssentials. From shop BiomaneticEssentials. 5 out of 5 stars (27) 27 reviews $ 179.00 FREE shipping Favorite Add to 20 pk Magnets therapy biomagnetism - cover magnets 1 7/8' X 7/8' X 3/8' ferrite magnets pack of 20. Samarium cobalt permanent magnet has high magnetic energy product and high coercivity, its magnetic performance is better than alnico permanent magnet, ferrite permanent magnet, the maximum energy product can reach 239kj/m3 (30mgoe), it is alnico8 permanent magnet 3 times that of ferrite.

Rare earth magnets and ferrite magnets are all types of permanent magnets. They are made up of a material that, once charged, will remain magnetic for many years unless damaged. However, not all permanent magnets are the same. Rare earth and ferrite magnets have different strength and resilience because they are made of different metal alloys.

Ferrite magnet

For many years, all magnets have been natural magnets, such as lodestone, which is a kind of iron ore with magnetic properties. In 1952, magnets were first made of ferrite. By making magnets from ferrites, engineers can make magnets in any shape they want. By making the carefully manufactured mixture into ferrite magnets, a stronger magnetic field can be produced than in nature. Ferrite magnets are cheaper, stronger and soon become popular. Ferrite magnets are also called hard ferrite magnets or ferromagnets. They are made of strontium or barium ferrite.

Rare Earth magnet

There are two types of rare earth magnets: SmCo and NdFeB. SmCo and NdFeB magnets are called “rare earth” because they are made up of rare earth elements in the periodic table of elements. SmCo magnets were developed in the 1970s and were the first rare earth magnets produced. Nd-Fe-B magnets were listed in 1984.

Magnet

Relative intensity

The magnetic field intensity produced by the magnet is quantified by BHmax or maximum energy product, and the BHmax or maximum energy product is measured by MGOe. The higher the BHmax is, the greater the force of the magnet is. BHmax of ferrite magnet is 3.5, BHmax of SmCo is 26, NdFeB is the most powerful rare earth magnet, its BHmax is 40.

Relative Resistance of Thermal Stress

Properties

Magnets begin to lose strength when heated to a certain temperature (Tmax), so they should not operate outside that temperature. However, when cooled below Tmax, they will regain power. The Tmax of ferrite magnet is 300℃, that of SmCo magnet is 300℃, and that of NdFeB magnet is 150℃.

Relative durability

Magnets can resist not only thermal stress, but also other stresses. NdFeB magnets are fragile and difficult to process. They are also easy to corrode. SmCo magnets are slightly less brittle and difficult to process, but have high corrosion resistance. SmCo magnets are also the most expensive type of magnet. Ferrite magnets are cheaper than SmCo and NdFeB magnets, and have good demagnetization and corrosion resistance.

Ferrite and neodymium magnet have different advantages. Ferrite magnets are easy to magnetize. They are very corrosion resistant and generally do not require additional coatings for corrosion protection. They can resist the demagnetization of external magnetic fields. They are stronger than natural magnets, although many other types of magnets are stronger than them. They are relatively cheap. Neodymium magnets are the most powerful of all permanent magnets. A neodymium magnet can lift more than any other type of magnet of the same size. They are extremely resistant to demagnetization of external magnetic fields.

Ferrites and neodymium magnets also have different disadvantages. Ferrite magnets are very fragile. They can’t be used in machinery that is under great pressure or bending. If exposed to high temperatures (over 480 degrees Fahrenheit), they will be degaussed. They only have medium intensity magnetic field, which is not suitable for applications requiring strong magnetic field. Neodymium magnets are relatively more expensive than ferrite magnets. They are easy to rust and extra measures must be taken to protect them from corrosion. Neodymium magnets are also very fragile and break under pressure. If exposed to more than 175 to 480 degrees Fahrenheit, they lose their magnetism.

Ferrite magnets, also known as ceramic magnets, provide the lowest magnetic field strength of all permanent magnetic materials with a maximum energy product range of 0.8-5.3 MGOe. However, they are by far the most cost effective to manufacture in large volumes, which is a reason why they are commonly used for commercial, high volume production runs where space, and therefore size of the magnet is not a limiting factor. Ferrite magnets can generally be manufactured in individual blocks as large as 152mm x 101mm x 25mm (6in x 4in x 1in).

There are two types of ferrite magnets manufactured today, strontium ferrite (SrO.6Fe203) and barium ferrite (BaO.6Fe203). Strontium ferrite are the most popular as they provide the best magnetic properties. Below, you can see a list of all the commercial available strontium ferrite magnet grades and their magnetic properties.

GradeRemanence (BR)
mT
(KGS)
Coercive Force (Hcb)
kA/m
(kOe)
Intrinisc Coercive Force (Hcj)
kA/m
(kOe)
Max. Energy Product (BH) max
kJ/m3
(MGOe)
Max. Operating Temp
TW
Y8T200-235
(2.0-2.3)
160
(2.0)
280
(3.5)
6.5-9.5
(0.8-1.2)
180°C
Y10T200-235
(2.0-2.3)
160
(2.0)
280
(3.5)
6.4-9.6
(0.8-1.2)
180°C
Y20320-380
(3.2-3.8)
190
(2.4)
195
(2.4)
18-22
(2.3-2.8)
180°C
Y22H310-360
(3.1-3.6)
250
(3.1)
320
(4.0)
20-24
(2.5-3.0)
180°C
Y23320-370
(3.2-3.7)
190
(2.4)
230
(2.9)
20-25
(2.5-3.2)
180°C
Y25360-400
(3.6-4.0)
170
(2.1)
200
(2.5)
22.5-28.0
(2.8-3.5)
180°C
Y26H360-390
(3.6-3.9)
250
(3.1)
255
(3.2)
23-28
(2.9-3.5)
180°C
Y27H370-400
(3.7-4.0)
250
(3.1)
255
(3.2)
25-29
(3.1-3.6)
180°C
Y28370-400
(3.7-4.0)
210
(2.6)
220
(2.7)
26-30
(3.3-3.8)
180°C
Y30370-400
(3.7-4.0)
210
(2.6)
220
(2.7)
26-30
(3.3-3.8)
180°C
Y30BH380-390
(3.8-3.9)
235
(2.9)
245
(3.0)
27-30
(3.4-3.8)
180°C
Y30H380-415
(3.8-4.1)
300
(3.7)
335
(4.2)
27-32
(3.4-3.1)
180°C
Y32400-420
(4.0-4.2)
190
(2.4)
195
(2.4)
30.0-33.5
(3.8-4.2)
180°C
Y32H400-440
(4.0-4.4)
240
(3.0)
250
(3.1)
31-35
(3.9-4.4)
180°C
Y33410-430
(4.1-4.3)
250
(3.1)
255
(3.2)
31.5-35.0
(4.0-4.4)
180°C
Y33H410-430
(4.1-4.3)
270
(3.4)
275
(3.4)
31.5-35.0
(4.0-4.4)
180°C
Y34420-440
(4.2-4.4)
230
(2.9)
235
(2.9)
32.5-36.0
(4.1-4.5)
180°C
Y35430-450
(4.3-4.5)
240
(3.0)
240
(3.0)
33.1-38.2
(4.2-4.8)
180°C
Y36430-450
(4.3-4.5)
239
(3.0)
241
(3.0)
33.1-38.2
(4.2-4.8)
180°C
Y38440-460
(4.4-4.6)
305
(3.8)
310
(3.9)
36.6-40.6
(4.6-5.1)
180°C
Y40440-460
(4.4-4.6)
354
(4.4)
360
(4.5)
37.5-41.8
(4.7-5.3)
180°C

Unfortunately, there are different naming standards used in different markets. The above ‘Y’ nomenclature is a Chinese standard, and the most widely used. Less regularly used is the ‘C’ American nomenclature and the ‘HF’ European standard. The magnetic properties of each of the standards are comparable. If you are more familiar with the American or European standard, you may find the following quick reference guide useful.

Quick cross reference:-

C5 = Feroba 2 = Fer 2 = HF26/18 = Y30

C8/C8A = Feroba 3 = Fer 3 = Y30H-1

C1 = Y8T / Y10T

C7 = Y26H-2 C8B = Y33

C9 = Y30H-2

C10 = Y33H

C11 = Y34

C12 = Y30H-2

Ferrite magnets are non-conductive and will not corrode as they are essentially already made from rust (iron oxide) and therefore cannot corrode further. They also maintain their performance in high temperatures and can be used in temperatures up to 250 degrees Celsius before any loss in performance occurs. However, ferrite magnets are susceptible to demagnetisation by stronger magnetic fields, which is why you will not find rare earth and ferrite magnets working together in the same application. Uniquely, their resistance to demagnetisation actually improves as the working temperature rises making them particularly useful for electric motors.

Ferrite Magnet Manufacturer

Ferrite magnets are typically produced in standard shapes such as discs, arcs, blocks and rings rather some of the more intricate shapes that you will find rare earth magnets produced in. At Magnet Expert Ltd we have the capability to produce bespoke ferrite magnets; however tooling charges for bespoke ferrite magnets are often high due to the nature of the material and the manufacturing process. If you have an enquiry about ferrite magnets please give our experts a call today on 0845 5194701.