Available Ceramic Magnet Grades

Magnetic and Physical Characteristics

The range of Ceramic magnet alloy grades available from Dura Magnetics typically extends from 1.05 – 3.8 MGOe. This range allows for optimizing the cost, performance, and operational temperature resistance for a wide range of applications.
Ceramic magnets have the lowest Energy Density of the commercially viable alloys, but are by far the most cost effective.  Often, sacrificing “space” and using more Ceramic / ferrite magnet alloy is a very good-trade-off for the low cost.  As with all magnet alloys, Ceramic magnets should not be used as structural elements.  They are very inherently brittle and will fracture or chip easily when mechanically stressed.

Ceramic / Strontium Ferrite Magnets – Available Grades
Dura Magnet Grade	Residual Induction Br		Coercive Force Hc		Intrinsic Coercive Force Hci		Maximum Energy Product (BH)max		Max. Operating Temp.*
	Nominal		Nominal		Minimum		Nominal		Nominal
	k-Gauss	Tesla	k-Oersted	kA/m	k-Oersted	kA/m	MGOe	kJ/m3	°C	°F
Ceramic 1	2.3	.230	1.860	148	3.500	278	1.05	8.4	250°	482°
Ceramic 5	3.9	.390	2.400	200	2.500	198	3.4	27.6	250°	482°
Ceramic 8	3.9	.390	3.000	240	3.200	256	3.4	27.6	250°	482°
Ceramic 8B	4.0	.400	3.000	240	3.050	244	3.8	30.4	250°	482°
* The listed maximum operating temperatures are based on an adequate Length to Diameter ratio or a properly designed magnetic circuit. The listed values are for reference and validation must occur before one chooses a design path. Please consult a Dura technical representative before selecting or designing with Ceramic magnet alloy.

Reversible Temperature Coefficient – Ceramic (Strontium Ferrite) Magnets
Temperature Range (°C)	Induction Br (α) (%)/°C	Intrinsic Coercivity Hci (β) (%)/°C
20°C to 150°C	-0.2 to -0.3	0.2 to 0.5
α = Δ Br / Δ T * 100 (Br @ 20°C) [ΔT = 20°C – 150°C] β = Δ Hci / Δ T * 100 (Hci @ 20°C) [ΔT = 20°C – 150°C]

Ceramic Magnets – 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
The listed values are approximate and should be used as a reference. Any magnetic or physical characteristics should be substantiated before selecting a magnet material. Please engage Dura’s Design / Development team members before selecting a design path. * The effective resistance may change based on the powder blend. Barium Ferrite has higher resistivity than Strontium Ferrite. Some Ceramic magnets are a blend. To ensure the correct design path is chosen execute due diligence by evaluating the magnet alloy on a case by case basis.

The listed values are approximate and should be used as a reference.  Any magnetic or physical characteristics should be substantiated before selecting a magnet material.  Please engage Dura’s Design / Development team members before selecting a design path.