Ferrite/Ceramic Magnets

Overview
Ceramic magnet material (Ferrite) is one of the most cost effective magnetic materials manufactured in industry. The low cost is due to the cheap, abundant, and non-strategic raw materials used in manufacturing this alloy. Ceramic magnet material (Ferrite) is Strontium Ferrite. The permanent Ceramic magnets made with this material make themselves to large production runs. Ceramic magnet material (Ferrite) has a fair to good resistance to corrosion and it can operate in moderate heat.

Applications
Due to the low cost of ceramic magnets, they are mainly used in DC motors, automotive sensors, craft projects, teaching, door absorber, magnetic bike, health equipments, etc.

Ceramic/Ferrite magnets properties – US standards

Grade	Residual Induction Br.		Coercive Force Hcb.		Intrinsic Coercive Force Hcj.		Max. Energy Product BH.
	mT	KGs	KA/m	KOe	KA/m	KOe	KJ/m3	MGOe
C1	230	2.3	148	1.86	258	3.5	8.36	1.05
C5	380	3.8	191	2.4	199	2.5	27	3.4
C7	340	3.4	258	3.23	318	4.00	21.9	2.75
C8(=C8A)	385	3.85	235	2.95	242	3.05	27.8	3.5
C8B	420	4.2	232	2.913	236	2.96	32.8	4.12
C9	380	3.8	280	3.516	320	4.01	26.4	3.32
C10	400	4.0	288	3.617	280	3.51	30.4	3.82
C11	430	4.3	200	2.512	204	2.56	34.4	4.32

Ceramic/Ferrite magnets properties – International Electronics Committee standards

The standard from International Electronics Committee (IEC404-8-1) O×100=Y10T=C1   ×300=Y30=C5   O×330=Y30 BH
Grade	Allowed Value (min-typical)
	Residual Induction Br.		Coercive Force Hcb.		Intrinsic Coercive Force Hcj.		Max. Energy Product BH.
	mT	KGs	KA/m	KOe	KA/m	KOe	KJ/m3	MGOe
HF8/22	200-220	2.00-2.20	125-140	1.57-1.76	220-230	2.76-2.89	6.5-6.8	0.8-1.1
HF20/19	320-333	3.20-3.33	170-190	2.14-2.39	190-200	2.39-2.51	20.0-21.0	2.5-2.7
HF20/28	310-325	3.10-3.25	220-230	2.76-2.89	280-290	3.52-3.64	20.0-21.0	2.5-2.7
HF22/30	350-365	3.50-3.65	255-265	3.20-3.33	290-300	3.64-3.77	22.0-23.5	2.8-3.0
HF24/16	350-365	3.50-3.65	155-175	1.95-2.20	160-180	2.01-2.26	24.0-25.5	3.0-3.2
HF24/23	350-365	3.50-3.65	220-230	2.76-2.89	230-240	2.89-3.01	24.0-25.5	3.0-3.2
HF24/35	360-370	3.60-3.70	260-270	3.27-3.39	350-360	4.40-4.52	24.0-25.5	3.0-3.2
HF26/16	370-380	3.70-3.80	155-175	1.95-2.20	160-180	2.01-2.26	26.0-27.0	3.2-3.4
HF26/18	370-380	3.70-3.80	175-190	2.20-2.39	180-190	2.26-2.39	26.0-27.0	3.3-3.4
HF26/24	370-380	3.70-3.80	230-240	2.89-3.01	240-250	3.01-3.14	26.0-27.0	3.3-3.4
HF26/26	370-380	3.70-3.80	230-240	2.89-3.01	260-270	3.27-3.39	26.0-27.0	3.3-3.4
HF26/30	385-395	3.85-3.95	260-270	3.27-3.39	300-310	3.77-3.89	26.0-27.0	3.3-3.4
HF28/26	385-395	3.85-3.95	250-265	3.14-3.33	260-275	3.27-3.45	28.0-30.0	3.5-3.8
HF28/28	385-395	3.85-3.95	260-270	3.27-3.39	280-290	3.50-3.60	28.0-30.0	3.5-3.8
HF30/26	395-405	3.95-4.05	250-260	3.14-3.33	260-270	3.27-3.39	30.0-31.5	3.8-3.9
HF32/17	410-420	4.10-4.20	160-180	2.01-2.26	165-175	2.07-2.20	32.0-33.0	4.0-4.1
HF32/22	410-420	4.10-4.20	215-225	2.70-2.83	220-230	2.76-2.89	32.0-33.0	4.0-4.1
HF32/25	410-420	4.10-4.20	240-250	3.01-3.14	250-260	3.14-3.27	32.0-33.0	4.0-4.1

More about ceramic magnets
Hard Ferrite (ceramic) magnets, composed of barium or strontium, were developed in the early 1960's as an alternative to the more expensive metallic magnets. This class of magnet is very hard, brittle and possesses lower energy characteristics compared to other magnetic materials. However, it is very popular and widely used because of its excellent resistance to demagnetizaion, corrosion, and the advantageous pricing.

Ferrite magnets are manufactured by pressing, sintering, or injection molding. These magnets can be both anisotropic and isotropic. Anisotropic grades are oriented in the manufacturing direction and must be magnetized in the direction of orientation. Isotropic grades are not oriented and can be magnetized in any direction.

More Applications of Ceramic Magnets
- Speaker Magnets
- DC brushless motors
- Magnetic Resonance Imaging (MRI)
- Magnetos used on lawnmowers and outboard motors
- DC permanent magnet motors (used in cars)
- Separators (separate ferrous material from non-ferrous)
- Used in magnetic assemblies designed for lifting, holding, retrieving and separating