Surface Treatment of Neodymium Magnet
The sintered neodymium iron boron permanent magnet material is produced by powder metallurgy technology. It is a kind of powder material with very strong chemical activity. There are tiny pores and cavities inside, which are easily corroded and oxidized in the air. The experimental results show that a 1cm³ sintered NdFeB permanent magnet will be completely oxidized and corroded if placed in the air at 150°C for 51 days. After the magnetic material is corroded or damaged, the magnetic properties will be attenuated or even lost over time, which will affect the performance and life of the whole machine, so strict anti-corrosion treatment must be carried out before use.
Zinc Plated
Nickel Plated
Gold Plated
Epoxy Plated
Teflon Plated
Corrosion Resistance of Neodymium Magnets with Different Coatings
| Coating Type | Processing Methods | Color | Thickness | SST (35℃, 5%NaCl) | PCT (85℃, 85%RH) | HAST (120℃, 0.2MPa, 100%RH) |
|---|---|---|---|---|---|---|
| Phosphate | Passivation | Dark Grey | 1 ~ 3 μm | 2 hours | - | - |
| Blue White Zn | Electroplating | Bright Blue | 4 ~ 15 μm | 24 hours | - | - |
| Color Zn | Electroplating | Silver White | 4 ~ 15 μm | 48 hours | - | - |
| Ni | Rack Electroplating | Silver | 5 ~ 20 μm | 16 hours | 168 hours | 48 hours |
| Ni | Barrel Electroplating | Silver | 5 ~ 20 μm | 48 hours | 168 hours | 48 hours |
| Chemical Ni | Rack Electroless Plating | Dark Silver | 3 ~ 20 μm | 24 hours | 168 hours | 48 hours |
| Chemical Ni | Barrel Electroless Plating | Dark Silver | 3 ~ 20 μm | 72 hours | 168 hours | 48 hours |
| NiCuNi | Rack Electroplating | Silver | 5 ~ 20 μm | 16 hours | 168 hours | 48 hours |
| NiCuNi | Barrel Electroplating | Silver | 5 ~ 20 μm | 48 hours | 168 hours | 48 hours |
| NiSn | Electroplating | Silver | 5 ~ 20 μm | 72 hours | 168 hours | 96 hours |
| NiAg | Electroplating | Silver | 5 ~ 20 μm | 72 hours | 168 hours | 96 hours |
| NiAu | Electroplating | Golden | 5 ~ 20 μm | 72 hours | 168 hours | 96 hours |
| Epoxy Resin | Electrophoresis | Any | 12 ~ 20 μm | 72 hours | 168 hours | 96 hours |
| Al | Vapour Deposition | Bright Silver | 2 ~ 15 μm | 24 hours | 168 hours | 24 hours |
| Coating Type | Processing Methods | Color | Thickness | SST (35℃, 5%NaCl) |
|---|---|---|---|---|
| Phosphate | Passivation | Dark Grey | 1 ~ 3 μm | 2 hours |
| Blue White Zn | Electroplating | Bright Blue | 4 ~ 15 μm | 24 hours |
| Color Zn | Electroplating | Silver White | 4 ~ 15 μm | 48 hours |
| Ni | Rack Electroplating | Silver | 5 ~ 20 μm | 16 hours |
| Ni | Barrel Electroplating | Silver | 5 ~ 20 μm | 48 hours |
| Chemical Ni | Rack Electroless Plating | Dark Silver | 3 ~ 20 μm | 24 hours |
| Chemical Ni | Barrel Electroless Plating | Dark Silver | 3 ~ 20 μm | 72 hours |
| NiCuNi | Rack Electroplating | Silver | 5 ~ 20 μm | 16 hours |
| NiCuNi | Barrel Electroplating | Silver | 5 ~ 20 μm | 48 hours |
| NiSn | Electroplating | Silver | 5 ~ 20 μm | 72 hours |
| NiAg | Electroplating | Silver | 5 ~ 20 μm | 72 hours |
| NiAu | Electroplating | Golden | 5 ~ 20 μm | 72 hours |
| Epoxy Resin | Electrophoresis | Any | 12 ~ 20 μm | 72 hours |
| Al | Vapour Deposition | Bright Silver | 2 ~ 15 μm | 24 hours |