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10 Cromac Place
The Gasworks
Belfast BT7 2DH
Tel: +44 (0) 2890 271001
Fax: +44 (0) 2890 271002
SmCo
Samarium Cobalt magnets were the first of the rare earth materials developed and has been in use since the 1960's.
Two versions of the material 1:5 and 2:17 the latter being richer in cobalt and thus having higher energy product values.
The main uses for SmCo magnets remain in areas where a high energy product is required yet the material must resist either high ambient temperatures or a humid or salt based environment. SmCo is chemically quite inert and does not oxidise readily. Likewise it has a very low temperature co-efficient and the demagnetisation curve remains linear in the 2nd quadrant for large rises in temperature up to 800oC.
SmCo however has some issues regarding its usage. Firstly due to the high cobalt content it is a relatively expensive material. Secondly as it is sintered it is limited in use to geometric shapes. The sintered material is also quite fractous meaning mechanical damage can easily be caused.
Magnetic Characteristics of Sintered Samarium Cobalt
| Material | Residual Flux Density | Coercive Force |
Mininum Intrinsic Coercive Force |
Max Energy Product |
Curie Temp |
||
| Br | Hcb | Hcj | (BH)max | ºC | |||
| T | kGs | kA/m | kA/m | kJ/m3 | |||
| Quality | Grade | Sintered Samarium Cobalt | |||||
| SmCo (1:5) |
GSS-18 | 0.85 - 0.9 | 8.5 - 9.0 | 620 - 648 | 1194 - 1513 | 127 - 143 | 750 |
| GSS-20 | 0.92 - 0.96 | 9.2 - 9.6 | 653 - 717 | 1194 - 1513 | 150 - 167 | 750 | |
| GSS-22 | 0.96 - 1.0 | 9.6 - 10.0 | 730 - 770 | 1194 - 1513 | 175 - 190 | 750 | |
| SmCo (2:17) | GSS-23 | 0.95 - 1.02 | 9.5 - 10.2 | 637 - 732 | 1433 - 1990 | 175 - 190 | 800 |
| GSS-25 | 1.02 - 1.05 | 10.2 - 10.5 | 748 - 796 | 1433 - 1990 | 195 - 215 | 800 | |
| GSS-27 | 1.05 - 1.08 | 10.5 - 10.8 | 746 - 796 | 1433 - 1831 | 205 - 220 | 800 | |
| GSS-28 | 1.02 - 1.10 | 10.2 - 11.0 | 420 | 440 - 520 | 205 - 220 | 800 | |
| GSS-29 | 1.08 - 1.10 | 10.8 - 11.0 | 780 | 955 - 1195 | 220 - 240 | 800 | |
| GSS-30 | 1.08 - 1.15 | 10.8 - 11.5 | 420 | 440 - 520 | 220 - 240 | 800 | |
Magnetic & Physical Properties of Compression Bonded SmCo
| Material | Remanence Br | Coercivity Hcb |
Intrinsic Coercivity Hcj |
Max. Energy Product |
Max Operating Temp |
||
| T | KGs | kA/m | kA/m | kJ/m3 | ºC | ||
| SmCo (1:5) |
GSSB-5 | 0.4 | 4.0 | 280 | 800 | 40 | 120 |
| GSSB-7 | 0.5 | 5.0 | 320 | 800 | 57.5 | 120 | |
| SmCo (2:17) |
GSSB-9 | 0.6 | 6.0 | 360 | 800 | 72.5 | 120 |
| GSSB-11 | 0.7 | 7.0 | 400.0 | 800 | 87.5 | 120 | |
