Sintered Samarium Cobalt Magnets

1: 5 type and 2:17 type sintered Samarium Cobalt magnets are called as the first generation and second generation of rare earth permanent magnets. 2:17 type is developed based on 1:5 type. Neodymium magnets dominated the market of rare earth permanent magnets since its inception and then Samarium Cobalt magnets are marginalized seriously due to magnetic performance, complex processing technologies, and costs. But in fact, sintered Samarium Cobalt magnet is still playing an irreplaceable role in high-temperature and high temperature stability applications which is not possible for Neodymium magnets. The research of high-performance sintered Samarium Cobalt magnets has never stopped, thus complex multistage heating treatment and microstructure control promoted magnetic performance of Samarium Cobalt magnets to an extreme. United States Department of Defense demanded that enhance the maximum operating temperature of sintered Samarium Cobalt magnet to the 500 degrees Celsius from 300 degrees Celsius to meet the new applications in aerospace in 1997. In the meanwhile, some higher high-end applications like travelling wave tube and internal device also asked reversible temperature coefficient of sintered Samarium Cobalt magnets should have small enough absolute value. Therefore, TbCu7-type structure Sm2Co7-based magnets emerged and gained widely concern.

Sintered Samarium Cobalt Magnets-Main

Manufacturing Process of Sintered Samarium Cobalt Magnets

Sintered Samarium Cobalt Magnets-Manufacturing

Magnetic Properties of Sintered Samarium Cobalt Magnets

MaterialGrade

Remanence

Br

Coercivity

Hcb

Intrinsic Coercivity

Hcj

Max.

Energy

Product

(BH)max

Curie

Temp

Tc

Max. Oper Tem.

Tw

Temp. Coeff. of BrTemp. Coeff. of Hcj
TkGskA/mKOekAkOekJ/m3MGOe%/℃%/℃
SmCo5RECo5-16S0.79-0.847.9-8.4620-6607.8-8.3≥1830≥23.0118-13515-17750250-0.035-0.28
RECo518S0.84-0.898.4-8.9660-7008.3-8.8≥1830≥23.0135-15117-19750250-0.040-0.28
RECo520S0.89-0.93 8.9-9.3684-7328.6-9.2≥1830≥23.0150-16719-21750250-0.045-0.28
RECo522S0.92-0.96 9.2-9.6710-7568.9-9.5≥1830≥23.0167-18321-23750250-0.045-0.28
RECo524S0.96-1.00 9.6-10.0740-7889.3-9.9≥1830≥23.0183-19923-25750250-0.045-0.28
(SmGd)Co5 LTC-100.62-0.666.2-6.6485-5176.1-6.5≥1830≥23.075-889.5-11.0750300

20-100℃: +0.0156

100-200℃: +0.0087

200-300℃: +0.0007

– 
Sm2(Co,Fe,Cu,Zr)17RE2Co17-24H0.95-1.029.5-10.2692-7648.7-9.6≥1990≥25.0175-19122-24800350-0.025-0.20
RE2Co17-26H1.02-1.0510.2-10.5740-7889.4-10.0≥1990≥25.0191-20724-26800350-0.030-0.20
RE2Co17-28H1.03-1.0810.3-10.8756-8129.5-10.2≥1990≥25.0207-22026-28800350-0.035-0.20
RE2Co17-30H1.08-1.1010.8-11.0788-8359.9-10.5≥1990≥25.0220-24028-30800350-0.035-0.20
RE2Co17-32H1.10-1.1311.0-11.3812-86010.2-10.8≥1990≥25.0230-25529-32800350-0.035-0.20
RE2Co17-220.93-0.979.3-9.7676-7408.5-9.3≥1433≥18.0160-18320-23800300-0.020-0.20
RE2Co17-240.95-1.029.5-10.2692-7648.7-9.6≥1433≥18.0175-19122-24800300-0.025-0.20
RE2Co17-261.02-1.0510.2-10.5748-7969.4-10.0≥1433≥18.0191-20724-26800300-0.030-0.20
RE2Co17-281.03-1.0810.3-10.8756-8129.5-10.2≥1433≥18.0207-22026-28800300-0.035-0.20
RE2Co17-301.08-1.1010.8-11.0788-8359.9-10.5≥1433≥18.0220-24028-30800300-0.035-0.20
RE2Co17-32
1.10-1.1311.0-11.3812-86010.2-10.8≥1433≥18.0230-25529-32800300-0.035-0.20
RE2Co17-26M1.02-1.0510.2-10.5676-7808.5-9.8955-143312-18191-20724-26800300-0.035-0.20
RE2Co17-28M1.03-1.0810.3-10.8676-7968.5-10.0955-143312-18207-22026-28800300-0.035-0.20
RE2Co17-30M1.08-1.1010.8-11.0676-8358.5-10.5955-143312-18220-24028-30800300-0.035-0.20
RE2Co17-32M1.10-1.1311.0-11.3676-8528.5-10.7955-143312-18230-25529-32800300-0.035-0.20
RE2Co17-24L0.95-1.029.5-10.2541-7166.8-9.0636-9558-12175-19122-24800250-0.025-0.20
RE2Co17-26L
1.02-1.0510.2-10.5541-7486.8-9.4636-9558-12191-20724-26800250-0.035-0.20
RE2Co17-28L
1.03-1.0810.3-10.8541-7646.8-9.6636-9558-12207-22026-28800250-0.035-0.20
RE2Co17-30L1.08-1.1510.8-11.5541-7966.8-10.0636-9558-12220-24028-30800250-0.035-0.20
RE2Co17-32L1.10-1.1511.0-11.5541-8126.9-10.2636-9558-12230-25529-32800250-0.035-0.20
(Sm,Er)2(Co,Tm)17LTC-160.81-0.858.1-8.5605-6697.6-8.4≥1592≥20117-12714-16840300

-50-20℃: +0.005

20-100℃: -0.008

100-200℃: -0.008

200-300℃: -0.011

 LTC-18 0.85-0.908.5-9.0629-7087.9-8.9≥1592 ≥20127-14316-18840300
 LTC-200.90-0.949.0-9.4661-7328.3-9.2≥1592 ≥20143-15918-20840300
 LTC-220.94-0.979.4-9.7685-7408.6-9.3≥1592 ≥20159-17520-22840300
  • The above-mentioned data of magnetic properties and physical properties are given at room temperature.
  • The max working temperature of magnet is changeable due to length-diameter ratio, coating thickness and other environment factors.

Physical Properties of Sintered Samarium Cobalt Magnets

Parameters Unit SmCo5 Sm2Co17
Density / ρ g/cm3 8.1-8.5 8.3-8.5
Vickers Hardness HV 450-500 500-600
Compressive Strength MPa 420-680 700-830
Electrical Resistivity Ω·cm (5-6)x10-5 (8-9)x10-5
Coeff. of Thermal Expansion 10-6/K

C⊥: 13

C∥: 6

C⊥: 11

C∥: 8

Performance Difference between Different Magnetic Material

Material

(BH)max

MGOe

Hcj

kOe

Temper. Coeff. of Br

%/℃

Max. Operating Temper

Anti-corrosition Capability
SmCo516-2515-25-0.05200-250Good
Sm2Co1722-326-30-0.03250-350Good
Nd2Fe14B26-5212-33-0.1180-230Bad
Ferrite3.0-4.53.0-4.5-0.19200-300Good
AlNiCo5-101.0-1.8-0.03450-500Excellent

Notes:

  • Actually, sintered Samarium Cobalt magnets are not suitable to be structure part due to inherent brittleness.
  • SmCo5 magnets are relatively easier to machine compared to Sm2Co17 magnets.
  • Customers who purchase non-magnetize Samarium Cobalt magnets should equip appropriate magnetizing equipment to ensure saturated magnetization.
  • SDM also serve coated Samarium Cobalt magnets to use under harsh environments.