Rare earth-iron-boron (REFeB) Magnets IEC Standard
The International Electrotechnical Commission (IEC) published the standard IEC 60404-8-1:2015 for magnetically hard materials (permanent magnets). In this standard, the part of Rare earth-iron-boron (REFeB) magnets’ magnetic properties and densities is shown in the table below.
In the REFeB magnets, the RE element is mainly neodymium (Nd), and the manufacturing method is a powder sintering process, so REFeB magnets are also known as sintered NdFeB magnets. China supplies most of the sintered NdFeB magnets in the global market, for those overseas customers using the IEC standard, it is necessary to compare the Chinese standard with the IEC standard. In the left column of the table, it lists some China grades of sintered NdFeB magnets, which are identical with IEC standard for REFeB magnets.
| China grade e+ | Magnetic properties and densities of REFeB magnets (IEC 60404-8-1:2015) | |||||||
|---|---|---|---|---|---|---|---|---|
| Brief designation | Code number | Maximum BH product | Remanent flux density | Coercivity | Coercivity | Relative recoil permeability | Density | |
| (BH)max | Br | HcB | HcJ | μrec | ρ | |||
| kJ/m3 | mT | kA/m | kA/m | - | Mg/m3 | |||
| N/A | REFeB 170/190 | R7-1-1 | 170 | 980 | 700 | 1900 | 1.05 | 7.5 to 7.7 |
| N28H | REFeB 210/130 | R7-1-2 | 210 | 1060 | 790 | 1300 | ||
| N33M | REFeB 250/120 | R7-1-3 | 250 | 1130 | 840 | 1200 | ||
| N38 | REFeB 290/80 | R7-1-4 | 290 | 1230 | 700 | 800 | ||
| N28UH | REFeB 200/190 | R7-1-5 | 200 | 1060 | 760 | 1900 | ||
| N33SH | REFeB 240/180 | R7-1-6 | 240 | 1160 | 840 | 1800 | ||
| N38M | REFeB 280/120 | R7-1-7 | 280 | 1240 | 900 | 1200 | ||
| N42 | REFeB 320/88 | R7-1-8 | 320 | 1310 | 800 | 880 | ||
| N28EH | REFeB 210/240 | R7-1-9 | 210 | 1060 | 760 | 2400 | ||
| N33UH | REFeB 240/200 | R7-1-10 | 240 | 1160 | 840 | 2000 | ||
| N42H | REFeB 310/130 | R7-1-11 | 310 | 1300 | 900 | 1300 | ||
| N33EH | REFeB 250/240 | R7-1-12 | 250 | 1200 | 830 | 2400 | ||
| N35UH | REFeB 260/200 | R7-1-13 | 260 | 1210 | 840 | 2000 | ||
| N45H | REFeB 340/130 | R7-1-14 | 340 | 1330 | 920 | 1300 | ||
| N45 | REFeB 360/90 | R7-1-15 | 360 | 1350 | 800 | 900 | ||
| N50 | REFeB 380/100 | R7-1-16 | 380 | 1420 | 990 | 1000 | ||
| * e+ = equal or superior | Typical values of the parameters: Temperature coefficient of remanence α(Br) = -0.1 %/°C to -0.12 %/°C (for 20 °C to 100 °C) Temperature coefficient of coercivity α(HcJ) = -0.45 %/°C to -0.6 %/°C (for 20 °C to 100 °C) Curie temperature: 310 °C Maximum opertating temperature: 200 °C | |||||||