Ferrite (Ceramic) Block Magnets

Product Information

Ferrite magnets are permanent magnets, not rare earth magnets, it is mainly made from iron oxide and strontium carbonate by ceramic processing technology, also called ceramic magnets.
Ferrite magnets are brittle, can be manufactured by die pressing and then sintering, can be made into various shapes and sizes. Its normal operating temperature is between -40℃ and 250℃. Ceramic magnets are the most commonly used permanent magnet materials due to their low cost, easy to produce, excellent corrosion and demagnetization resistance properties. It can be produced either isotropic or anisotropic. C3, C5 & C8 magnets are anisotropic.

Ferrite magnets are easy to recognise due to their dark-grey colour. Unlike neodymium magnets, they don't need any coating thanks to their non-corrosive material. 

· Ferrite magnets are ideal for low cost applications.

· Ferrite magnets are also electrically insulating - they do not allow eddy currents inside them.

· Ferrite magnets are great for higher temperatures but not ideal in very cold applications.

Ferrite (Ceramic) Block Magnets Specification

Approximate Pull Information:

Coatings, rust, rough surfaces, and certain environmental conditions can significantly reduce the pull force. Please be sure to test the actual pull in your actual application. For critical applications, it is suggested that the pull be de-rated by a factor of 2 or more, depending on the severity of a potential failure. 

Standard Dimensional Tolerances for Ceramic Block & Bar Magnets

Standard dimensional tolerances for Ceramic Magnets based on the following dimensions:

+/- 0.005” on length & width dimensions ranging from 0.040” to 1.000”.

+/- 0.010” on length & width dimensions ranging from 1.001” to 2.000”.

+/- 0.015” on length & width dimensions ranging from 2.001” to 3.000”.

*Tolerance on thickness +/-0.005” regardless of size. 

Per your request or drawing

We can customized as required

Properties（Theoretical）

Features & Characteristics of Ferrite Magnets

Ferrite magnets are superb in damp, wet or marine environments – Ferrite magnets are corrosion free. Because the iron is already in a stable oxidized form in its structure, the iron cannot oxidize (“rust”) any further when in water. Strontium Ferrite (SrO.6Fe2O3) magnets and Barium Ferrite (BaO.6Fe2O3) magnets are the two types of ceramic Ferrite magnet. The Strontium Ferrite magnets are the most commonly manufactured due to having stronger magnetic properties.

The Ferrite magnets (Ceramic magnets) have a characteristic “pencil lead” colour (i.e. a dark grey colour). They are ferrimagnetic in magnetic performance (good magnetic field and power but, size for size, not as powerful as NdFeB or SmCo). They are extremely popular in motor, generator, loudspeaker and marine designs but are found in almost all industries. e.g. Automotive, Sensor, Machines, Aerospace, Military, Advertising, Electrical/Electronic, Academic, Design House, and R&D. Ferrite magnets can be used at temperatures up to a maximum of +250 degrees C (in a few situations perhaps up to +300 degrees C). There are presently 27 grades of Ferrite Magnet available. The two main grades used today are C5 (also known as Feroba2, Fer2, Y30 and HF26/18) and C8 (also known as Feroba3, Fer3 and Y30H-1). C 5 / Y30 is a general choice of Ferrite Magnet for applications such as overband magnets. C8 / Y30H-1 is a better choice for applications such as loudspeakers and sometimes also motors (C8 has a similar Br to C5 but has a higher Hc and Hci). Ferrite magnets can be produced in many shapes and sizes. Machining to size is limited to grinding processes - the electrically insulating Ferrite material does not allow wire spark erosion. As such, the main shapes are blocks, discs, rings, arcs, and rods. 

Advantages & Disadvantages of Ferrite (Ceramic) Magnets

Advantages 

· Do not corrode in water.

· Can be used up to +250 degrees C (482F)

· Sometimes up to +300 degrees C (572F) in special circumstances.

· High coercivity (Hci) that increases as magnet heats up.

· Electrically insulating.

· Relatively low cost - good for cost saving projects.

Disadvantages

· Not as strong as  Neodymium Rare Earth Magnets – typically offering around 1/7th the pull force of similarly sized NdFeB.

· Specialised shapes can carry tooling charges.

· When taken to around -20 degrees C (-4F) and colder, the Intrinsic Coercivity (Hci) falls to a level that risks the magnet possibly starting to demagnetise (depending on the shape and the application).

Neodymium Magnets VS Ferrite Magnets
The differences between NdFeB magnets and Ferrite magnets mainly include the following points:
1. In the appearance, Ferrite magnets are loose, with no metal luster, and generally supplied without plating. Ferrite magnets are usually in black color and are oxides, very stable, and not easy to rust. NdFeB magnets are alloys which are easy to oxidize and usually supplied with coating or they can be rusted easily. The surface of NdFeB is silvery white, with metallic luster or other colors.
2. The magnetic energy difference between NdFeB and Ferrite is huge. Magnetic energy product of NdFeB magnets can reach 53MGOe, while that of ferrite magnets is 6MGOe.
3. In terms of price, ferrite magnets are much cheaper than Nd-Fe-B magnets. Ferrite is mainly ferric oxide, while neodymium iron boron is mainly made of rare earth and iron.
4. Comparing with neodymium magnets, which easily demagnetize in high temperature, ferrite magnets have excellent temperature –resistance, of which magnetic strength are not readily weaken.
5. Ferrite magnets are easy to be magnetized with multi poles, but neodymium magnets are more difficult to do multi-pole magnetization direction.

Remark:
With high permeability, cheap price and high temperature resistance, ferrite magnets are applicable to working environment of low frequency. They are often used in loudspeakers and voice box.
Due to small size, light weight and strong magnetic strength, neodymium magnets have variety of applications and good mechanical characteristics. They are cost-effective and widely used in modern industry and electronic technology.

Typical Applications for Ferrite (Ceramic) Magnets

· Motors and Generators

· Meters

· Marine applications

· High temperature applications.

· Lower cost pot magnets and clamping systems

· Loudspeakers

· Overband magnets

Packing of Ferrite (Ceramic) Block Magnets

Standard Packing:

Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 440 gallon liquid totes Special package is available on request.

ATTs’ Ferrite (Ceramic) Block Magnets are carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition.