Samarium Cobalt Magnets

Sintered Samarium Cobalt (SmCo) magnets are a highly sophisticated magnetic material composed primarily of samarium, cobalt, and select rare earth elements. It can be categorized into two main variants based on the proportion of its constituent elements: SmCo5 and Sm2Co17. As second-generation rare earth permanent magnets, SmCo magnets stand out for its exceptional magnetic properties, combining a notably high magnetic energy product and dependable coercivity.

What truly sets SmCo apart is its remarkable temperature resilience, a characteristic that surpasses other rare earth magnetic materials. In comparison to Neodymium Iron Boron (NdFeB), SmCo magnets are particularly well-suited for operating in high-temperature environments, comfortably exceeding 200°C. Furthermore, these magnets exhibit an inherent resistance to corrosion and oxidation, often obviating the need for additional protective coatings.

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Physical Properties

	Density	Curie Temperature	Vickers Hardness	Compress Strength	Electrical Resistivity	Bend Strength	Tensile Strength	Thermal Expansion Coefficient
	g/cm³	K	MPa	MPa	Ω·cm	MPa	MPa	10^-6/℃
SmCo (1:5)	8.1-8.3	1000	450-500	1000	5-6x10^-5	150-180	400	//6 ⊥12
SmCo (2:17)	8.3-8.5	1100	550-600	800	8-9x10^-5	130-150	350	//8 ⊥11

Magnetic Properties

Material	Grade	Br		Hcb		Hcj		(BH)max		Tc	Tw
Material	Grade	kGs	mT	kA/m	kOe	kA/m	kOe	KJ/m³	MGOe	°C	°C
SmCo (1:5)	SM-18	8.5	850	620	7.8	≥1350	≥17	145~150	17~19	750	250
	SM-20	9.0~9.6	900~960	653~717	8.2~9.0	1194~1513	15~19	150~175	19~22	750	250
	SM-22	9.3~10.0	930~1000	660~772	8.3~9.7	1194~1751	15~22	159~191	20~24	750	250
	SM-24	9.6~10.4	960~1040	660~780	8.3~9.8	1194~1751	15~22	175~207	22~26	750	250
SmCo (2:17)	SMG-24	9.5~10.2	950~1020	637~732	8.0~9.2	1433~1990	18~25	175~190	22~24	800	300
	SMG-26	10.2~10.5	1020~1050	748~796	9.4~10.0	1433~1990	18~25	195~215	24~26	800	300
	SMG-28	10.5~10.8	1050~1080	756~796	9.5~10.0	1433~1831	18~23	205~220	26~28	800	300
	SMG-30	10.7~11.2	1070~1120	677~820	8.5~10.3	≥1194	≥15	223~247	28~31	800	300
	SMG-32	10.9~11.5	1090~1150	677~820	8.5~10.3	≥955	≥12	238~262	29~32	800	300

Temperature Characteristics

SmCo magnets can operate at temperatures up to 350°C, depending upon the grade and permeance coefficient. Sm2Co17 materials exhibit superior temperature characteristics as compared to the Sm1Co5 types. SmCo magnets have extremely resistant to demagnetization, and good temperature stability (maximum use temperatures between 250 °C and 550 °C).

Surface Treatment

The corrosion resistance of SmCo is considered good while that of NdFeB is considered poor. Coatings for corrosion resistance are therefore not generally required for SmCo magnets. We also can offer coatings such as Ni, Zn, or Epoxy if they are used in corrosive environment.

Application

The versatility of SmCo permanent magnets finds application across a diverse range of industries where magnetic stability and performance are paramount. Notably, it is a cornerstone material in critical sectors such as aerospace, defense, telecommunications, medical instrumentation, and electric motors, where demanding operating conditions necessitate the exceptional magnetic properties and reliability that SmCo magnets provide.