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SmCo Magnets

 

Samarium Cobalt permanent magnet is widely used second generation high energy material. Using Samarium and Cobalt as its rare earth element, it exhibits high magnetic performance characteristics in energy product and coercive force. There are two compositions of magnets in this family: Sm1Co5 and Sm2Co17. The highest commercially available energy products of Sm2Co17 are in the 30MGOe range.

 

MAGNETIC CHARACTERISTICS

 

Sm 1 Co 5 Sm 2 Co 17
SC-16 SC-20 SC-24 SC-27
Residual Flux Density Br (KGauss) 8.0 – 9.0 9.0 – 10.0 9.8 – 10.2 10.2 – 11.5
Coercive Force bHc (KOe) 7.0 – 8.0 8.0 – 9.5 6.0 – 6.8 8.2 – 9.5
Intrinsic Coercive Force iHc (KOe) 20 – 25 18 – 23 6.2 – 7.0 13 – 22
Maximum Energy Product BHmax (MGOe) 15 – 19 19 – 23 22 – 24 24 – 28

 Note: Other grades of SmCo materials are available upon request

 

Various SmCo Magnets
Various SmCo Magnets

 

SmCo magnets are better able to withstand higher temperatures than other rare earth magnets. The Sm2Co17 type exhibits superior temperature property as compared to the Sm1Co5 type. The Curie temperature for Sm2Co17 could reach as high as 1073 º K / 800 º C. Temperature coefficients for SmCo materials are in the range – 0.04 % / º C for Br and – 0.30 % / º C for iHc.

SmCo magnets are highly prone to chipping and cracking, and specialized machining techniques are required. Press-fit assembly is not recommended because of their brittle nature. The SmCo materials are sensitive to thermal shock and hairline fractures can occur if subjected to thermal shock. Where cosmetic appearance of a magnet is important, this should be specified to us prior to ordering.

SmCo magnets require extremely high magnetizing fields. It requires fields of about 40 KOe in order to be saturated. This is not common to produce and large power supplies in conjunction with carefully designed magnetizing fixtures must be used. A special consideration must be given to this when designing complex assemblies if it is intended to magnetize after assembly.

WARNING: Due to their extremely high magnetic strength and brittle nature, SmCo magnet parts must be handled very carefully to prevent injury to personnel and damage to the magnets. Receiving and assembly personnel must be pre-warned about the dangers of handling these magnet parts.