Samarium Cobalt (SmCo) Magnets

Extremely strong rare earth magnets, Samarium Cobalt magnets (SmCo) are composed of samarium, cobalt, and iron. Not sure if samarium cobalt is the best material for your application? Review our permanent magnetic materials comparison for more information.

Manufacturing - In general, the elements are melted together and milled into a powder that is dry-pressed to shape in the presence of a magnetic field. The material is then sintered, aged, ground to dimension, magnetized, and tested. They are called “rare earth” magnets because the elements of samarium cobalt are classified as such in the lanthanides section of the Periodic Table of the Elements.

Tolerances - For as-pressed material, tolerance on the thickness (direction of magnetization) is +/- .005”. Other dimensions are +/- 2.5% or +/- .010”, whichever is greater.

According to International Magnetics Association (IMA) standards, visual imperfections such as hairline cracks, porosity, and minor chips are commonly found in sintered metallic magnets. A chipped edge is considered acceptable if no more than 10% of the surface is missing. Cracks are acceptable as long as they do not extend across more than 50% of the pole surface.

Magnetizing and Handling - samarium cobalt magnets are very brittle and very strong magnetically. Therefore, it is crucial to handle these magnets with extreme care to avoid personal injury and damage to the magnets. Fingers can be severely pinched between attracting magnets. Magnets can chip if allowed to “jump at” an attracting object. It is highly recommended that when constructing rare earth magnetic assemblies, the magnets be magnetized after assembly. These magnets are NOT for children.

Machining - Since samarium cobalt magnet material is prone to chipping and cracking, it does not lend itself to conventional machining methods. It can, however, be abrasively ground, but only with the use of liberal amounts of coolant. The coolant minimizes heat fracturing and the risk of fires caused by oxidized grinding dust.

Typical Magnetic and Physical Properties of Samarium Cobalt

Samarium Cobalt Material	Density		Max. Energy Product BH (max)	Typical Residual Induction Br (max)	Coercive Force Hc (min)	Intrinsic Coercive Force (Hci)	Maximum Operating Temperature		Curie Temperature
	lbs/in³	g/cm³	MGO	Gauss	Oersteds	Oersteds	F°	C°	F°	C°
SmCo 18	0.296	8.2	16 - 18	8700	≥8100	≥16000	482	250	1382	750
SmCo 20	0.296	8.2	19 - 21	9200	≥8500	≥16000	482	250	1382	750
SmCo 22	0.299	8.3	20 - 22	9500	≥8900	≥16000	482	250	1382	750
SmCo 24	0.304	8.4	22 - 24	9900	≥9100	≥18000	662	350	1508	820
SmCo 26	0.304	8.4	24 - 26	10400	≥9400	≥18000	662	350	1508	820
SmCo 28	0.303	8.4	26 - 28	10700	≥9500	≥18000	662	350	1508	820
SmCo 30	0.303	8.4	28 - 30	11000	≥9900	≥18000	662	350	1508	820

Applications of Samarium Cobalt Magnets

Computer disc drives and sensors
Traveling wave tubes
Linear actuators and satellite systems
Motors where temporary stability is vital

Attributes of Samarium Cobalt Material

High resistance to demagnetization
High energy (magnetic strength is strong for its size)
Good to moderately high-temperature stability
Pricing for samarium cobalt is market sensitive

Master Magnetics is your magnet source for Samarium-Cobalt material. Shop our collection here.