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

Material Grade Remanence

 

Br

Coercivity

 

Hcb

Intrinsic Coercivity

 

Hcj

Max. Energy Product

 

(BH)max

Curie Temp.

 

Tc

Max. Operating Temp.

 

Tw

Temper. Coeff.

 

of Br

Temper. Coeff. of Hcj
T kGs kA/m kOe kA/m kOe kJ/m3 MOGe %/℃ %/℃
SmCo5 RECo5-16S 0.79-0.84 7.9-8.4 620-660 7.8-8.3 ≥1830 ≥23 118-135 15-17 750 250 -0.035 -0.28
RECo5-18S 0.84-0.89 8.4-8.9 660-700 8.3-8.8 ≥1830 ≥23 135-151 17-19 750 250 -0.040 -0.28
RECo5-20S 0.89-0.93 8.9-9.3 684-732 8.6-9.2 ≥1830 ≥23 150-167 19-21 750 250 -0.045 -0.28
RECo5-22S 0.92-0.96 9.2-9.6 710-756 8.9-9.5 ≥1830 ≥23 167-183 21-23 750 250 -0.045 -0.28
RECo5-24S 0.96-1.00 9.6-10.0 740-788 9.3-9.9 ≥1830 ≥23 183-199 23-25 750 250 -0.045 -0.28
(Sm,Gd)Co5 LTC(RECo5-10) 0.62-0.66 6.2-6.6 485-517 6.1-6.5 ≥1830 ≥23 75-88 9.5-11 750 250 20-100℃: +0.0156

 

100-200℃: +0.0087

200-300℃: +0.0007

Sm2(Co,Fe,Cu,Zr)17 RE2Co17-24H 0.95-1.02 9.5-10.2 692-764 8.7-9.6 ≥1990 ≥25 175-191 22-24 800 350 -0.025 -0.20
RE2Co17-26H 1.02-1.05 10.2-10.5 748-796 9.4-10.0 ≥1990 ≥25 191-207 24-26 800 350 -0.030 -0.20
RE2Co17-28H 1.03-1.08 10.3-10.8 756-812 9.5-10.2 ≥1990 ≥25 207-220 26-28 800 350 -0.035 -0.20
RE2Co17-30H 1.08-1.10 10.8-11.0 788-835 9.9-10.5 ≥1990 ≥25 220-240 28-30 800 350 -0.035 -0.20
RE2Co17-32H 1.10-1.13 11.0-11.3 812-860 10.2-10.8 ≥1990 ≥25 230-255 29-32 800 350 -0.035 -0.20
RE2Co17-22 0.93-0.97 9.3-9.7 676-740 8.5-9.3 ≥1433 ≥18 160-183 20-23 800 300 -0.020 -0.20
RE2Co17-24 0.95-1.02 9.5-10.2 692-764 8.7-9.6 ≥1433 ≥18 175-191 22-24 800 300 -0.025 -0.20
RE2Co17-26 1.02-1.05 10.2-10.5 748-796 9.4-10.0 ≥1433 ≥18 191-207 24-26 800 300 -0.030 -0.20
RE2Co17-28 1.03-1.08 10.3-10.8 756-812 9.5-10.2 ≥1433 ≥18 207-220 26-28 800 300 -0.035 -0.20
RE2Co17-30 1.08-1.10 10.8-11.0 788-835 9.9-10.5 ≥1433 ≥18 220-240 28-30 800 300 -0.035 -0.20
RE2Co17-32 1.10-1.13 11.0-11.3 812-860 10.2-10.8 ≥1433 ≥18 230-255 29-32 800 300 -0.035 -0.20
RE2Co17-26M 1.02-1.05 10.2-10.5 676-780 8.5-9.8 955-1433 12-18 191-207 24-26 800 300 -0.035 -0.20
RE2Co17-28M 1.03-1.08 10.3-10.8 676-796 8.5-10.0 955-1433 12-18 207-220 26-28 800 300 -0.035 -0.20
RE2Co17-30M 1.08-1.10 10.8-11.0 676-835 8.5-10.5 955-1433 12-18 220-240 28-30 800 300 -0.035 -0.20
RE2Co17-32M 1.10-1.13 11.0-11.3 676-852 8.5-10.7 955-1433 12-18 230-255 29-32 800 300 -0.035 -0.20
RE2Co17-24L 0.95-1.02 9.5-10.2 541-716 6.8-9.0 636-955 8-12 175-191 22-24 800 250 -0.025 -0.20
RE2Co17-26L 1.02-1.05 10.2-10.5 541-748 6.8-9.4 636-955 8-12 191-207 24-26 800 250 -0.035 -0.20
RE2Co17-28L 1.03-1.08 10.3-10.8 541-764 6.8-9.6 636-955 8-12 207-220 26-28 800 250 -0.035 -0.20
RE2Co17-30L 1.08-1.10 10.8-11.0 541-796 6.8-10.0 636-955 8-12 220-240 28-30 800 250 -0.035 -0.20
RE2Co17-32L 1.10-1.15 11.0-11.5 541-812 6.8-10.2 636-955 8-12 230-255 30-32 800 250 -0.035 -0.20
(Sm,Er)2(Co,Tm)17 LTC(RE2Co17-16) 0.81-0.85 8.1-8.5 605-669 7.6-8.4 ≥1592 ≥20 117-127 14-16 840 300 -50-20℃: +0.005
20-100℃: -0.008
100-200℃: -0.008
200-300℃: -0.011
LTC(RE2Co17-18) 0.85-0.90 8.5-9.0 629-708 7.9-8.9 ≥1592 ≥20 127-143 16-18 840 300
LTC(RE2Co17-20) 0.90-0.94 9.0-9.4 661-732 8.3-9.2 ≥1592 ≥20 143-159 18-20 840 300
LTC(RE2Co17-22) 0.94-0.97 9.4-9.7 685-740 8.6-9.3 ≥1592 ≥20 159-175 20-22 840 300
  • 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 Permanent Magnet Materials

Material (BH)max

 

MGOe

Hcj

 

kOe

Temper. Coeff. of Br

 

%/℃

Max. Operating Temper

 

Anti-corrosition Capability
SmCo5 16-25 15-25 -0.05 200-250 Good
Sm2Co17 22-32 6-30 -0.03 250-350 Good
Nd2Fe14B 26-52 12-33 -0.11 80-230 Bad
Ferrite 3.0-4.5 3.0-4.5 -0.19 200-300 Good
AlNiCo 5-10 1.0-1.8 -0.03 450-500 Excellent

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.