Rare earth neodymium magnet material contains lots of neodymium (Nd) and iron (Fe) which is easy to be oxidized and to cause demagnetization. Therefore permanent neodymium magnets must to do some surface treatment, such as NiCuNi, black epoxy, grey epoxy and Zn etc. Have you ever thought how to test the quality of neodymium magnet coating?

1. Visual Observation
Appearance is mainly through visual observation under natural light (sunlight, non-direct), or the equivalent of 40W fluorescent lamp. There should be no blistering, peeling, partial unplated and uneven shade, blot, water spots and the like.

2. Testing of Magnet Plating Thickness 
by X radial plating thickness tester

3. Drop Test
it is mainly for neodymium magnet with Zn coating

4. Cutting Test
it is commonly used for NdFeB magnet with Nickel plating. Glue the magnets on the 3M tape with the cutting section upward. Use the cutting knife to cut several 1mm×1mm arrayed squares on the surface of the coating, wipe off the scrap metal from the surface with a piece of clean paper, then glue the 3M tape on the surface and peel off immediately.

5. Adhesion Atrength Test
Put the neodymium magnet sample into oven, keeping the temperature 250℃ for 1hour, 1cycle.

6. PCT Test
Temperature 120℃, 100%RH, 2atm, test 24 hours, No cracks, bubbles, peeling, rust on the coating of magnet.

7. Salt Spray Test
Box temperature 35℃, 5%NaCl, PH value 6.5 - 7.2, test for 24 hours. No cracks, bubbles, peeling, rust on the magnet coating.

8. Constant Temperature & Moisture Test

Although magnet surface has been treated for the purpose of anti-rust, it still needs to pay attention the operating environment and storage environment.

If you want to purchase magnet and have special requirement for magnet coating, we can custom neodymium magnet based on your demand. Please feel free to contact us at sales@china-magnets-source-material.com