In 1966, Hoffer reported that YCo5 has a relatively large crystal anisotropy with a single easy axis of magnetization. Then Strnat reported a (BH)max of 40.6kJ/m3 for SmCo5 in 1967. Further improvement in (BH)max to 144.7kJ/m3 was reported in 1968 by Buschow. Discovery and development of SmCo5 magnet marked the arrival of the rare earth magnet. Thereby, SmCo5 magnet is generally known as the first generation of rare earth permanent magnetic material. Cobalt content in SmCo5 magnet is around 66wt% and thus accused of raw material cost. In addition, SmCo5 magnet had better machinability in comparison to Sm2Co17 magnet.
| Grade | Remanence Br | Coercivity Hcb | Intrinsic Coercivity Hcj | Max. Energy Product (BH)max | Curie Temp. Tc | Max. Ope. Tem. Tw | Temp. Coeff. of Br | Temp. Coeff. of Hcj | ||||
| T | kGs | kA/m | kOe | kA | kOe | kJ/m3 | MGOe | ℃ | ℃ | %/℃ | %/℃ | |
| RECo5-16S | 0.79-0.84 | 7.9-8.4 | 620-660 | 7.8-8.3 | ≥1830 | ≥23.0 | 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 | ≥23.0 | 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 | ≥23.0 | 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 | ≥23.0 | 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 | ≥23.0 | 183-199 | 23-25 | 750 | 250 | -0.045 | -0.28 |
| LTC(RECo5-10) | 0.62-0.66 | 6.2-6.6 | 485-517 | 6.1-6.5 | ≥1830 | ≥23.0 | 75-88 | 9.5-11.0 | 750 | 300 | 20-100℃: +0.0156 100-200℃: +0.0087 200-300℃: +0.0007 | – |
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