ccording the max working temperature, we can divide Sintered magnet to 7 grades, N grade is for 80 ℃,grade M is for 100℃,grade H is for 120℃,grade SH is for 120℃,grade UH is for 150℃ and grade EH is for 200℃,you according your demand to choose the grade which you need.
Mostly of rare earth permanent magnet always work do not at room temperature or under vacuum, in order to keep the accuracy of shape size and avoid the Corrosion and oxidation, we must make the coating on the surface.
Sometime, the customers have high demand of NdFeB anti-corrosion, antioxidant, we can design the magnet,add some elements, such as: niobium, vanadium, cobalt and other metal to replace part of the iron to catch the customer requirements of the acid and alkali resistant,antioxidant level, however, because of special material, we need MOQ for it.
salt spray test results for coating
| Commonly type of coating | Coating thickness(um) | Neutral salt spray test | ||||
| dark Ni | Cu | Shine Ni | Total | |||
Single-layer Ni | 25 | 25 | 24h | normal | ||
Double-layer Ni | 12 | 10 | 25 | 72h | better | |
| Dark Ni-Cu–shine Ni | 6.25 | 8.75 | 10 | 25 | 120h | excellent |
The main physical properties of sintered NdFeB
| magnetic properties | Parameters |
Density /g.cm3 VickersHardness HV Resistivity /υΩ.cm Compressivestrength/N.mm-2 Coefficient of ThermalExpansion (C⊥)/K-1 Coefficient of ThermalExpansion (C∥) /K-1 | 7.45 570 150 780 -4.8X10-6 -3.4X10-6 |
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