Ferrite Magnet | Industrial Magnet Supplier in China

Development history of ferrite magnets

Ferrite magnets (or hard ferrite) are developed at Philips Physics Laboratory in 1950s. They became commercially available in the 1960s due to its low cost and high magnetic performance. They are also called ceramic magnets because 1) the sintering process of this magnet material is similar to ceramic and 2) both are electrically insulating. Permanent magnets really penetrated into our everyday life with the commercialization of hard ferrite. Prior to ferrite magnets, only AlNiCo magnets had dominated the permanent magnet market.

What makes ferrite magnets different?

Comparing to other permanent magnets, ferrite magnet has a low maximum energy product of up to 5.5MGOe. However, its high coercivity and cost-effectiveness make it an ideal magnetic material for a variety of applications. Measuring by weight, it accounts for over 75% of the global permanent magnet consumption. Ferrite arc magnet is also an important component in electric motors.

low cost
high magnetic performance
high temperature resistance (≤ 250℃)
high resistance to demagnetization

Common grades are Y30, Y35, Y30BH magnet or C5, C8, etc. Strontium ferrite magnets are the most manufactured hard ferrite type.

Manufacturing process of sintered ferrite magnet

Grade - sintered hard ferrite magnet (SJ285-77)

Grade	Br		Hcb		Hcj		(BH)max
Grade	mT	kGs	kA/m	kOe	kA/m	kOe	kJ/m3	MGOe
Y20	320-380	3.2-3.8	135-190	1.70-2.38	140-195	1.76-2.45	18.0-22.0	2.3-2.8
Y22H	310-360	3.1-3.6	220-250	2.77-3.14	280-320	3.52-4.02	20.0-24.0	2.5-3.0
Y23	320-370	3.2-3.7	170-190	2.14-2.39	190-230	2.39-2.89	20.0-25.5	2.5-3.2
Y25	360-400	3.6-4.0	135-170	1.70-2.14	140-200	1.76-2.51	22.5-28.0	2.8-3.5
Y26H	360-390	3.6-3.9	220-250	2.77-3.14	225-255	2.83-3.21	23.0-28.0	2.9-3.5
Y27H	370-400	3.7-4.0	205-250	2.58-3.14	210-255	2.64-3.21	25.0-29.0	3.1-3.7
Y30	380-400	3.8-4.0	175-210	2.20-2.64	180-220	2.26-2.77	26.0-30.0	3.3-3.8
Y30BH	380-400	3.8-4.0	223-235	2.80-2.95	231-245	2.90-3.08	27.0-30.0	3.3-3.8
Y30H-1	380-400	3.8-4.0	230-275	2.89-3.46	235-290	2.95-3.65	27.0-32.0	3.4-4.0
Y30H-2	395-415	3.95-4.15	275-300	3.46-3.77	310-335	3.90-4.21	28.5-32.5	3.5-4.1
Y32	400-420	4.0-4.2	160-190	2.01-2.38	165-195	2.07-2.45	30.0-33.5	3.8-4.2
Y33	410-430	4.1-4.3	220-250	2.77-3.14	225-255	2.83-3.21	31.5~35.0	4.0-4.4
Y35	400-440	4.0-4.4	176-224	2.22-2.8	180-230	2.26-2.89	30.3-33.4	3.8-4.2

Grade - sintered hard ferrite magnet (MMPA-No.0100-00)

Grade	Br		Hcb		Hcj		(BH)max
Grade	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	27.0	3.4
C7	340	3.4	258	3.23	318	4.0	21.9	2.75
C8	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

Physical Properties of ferrite magnets

Ferrite Magnets – Typical Physical Properties
Property	Units	Value Ceramic (Strontium Ferrite)
Vickers Hardness	Hv	~ 1160 (7 Mohs)
Density	g/cm3	4.5 to 5.1
Curie Temp TC	°C	450 to 460
Curie Temp TF	°F	840 to 860
*Specific Resistance	μΩ⋅Cm	> 106
Bending Strength	kN/mm2	0.05 – 0.09
Tensile Strength	kN/mm2	.02 to .05
Thermal Expansion (∥)	°C-1	+11.0 to +16.0 x10-6
Thermal Expansion (⊥)	°C-1	‘+7.0 to +15.0 x 10-6

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