NdFeB magnets are tetragonal crystals formed by neodymium, iron, and boron (Nd2Fe14B). NdFeB magnets are widely used in electronics, electric machinery, medical equipment, toys, packaging, hardware machinery, aerospace and other fields. Common ones include permanent magnet motors, speakers, magnetic separators, computer disk drives, magnetic resonance imaging equipment and instruments, etc.
In order to avoid corrosion damage, the surface of the permanent magnet material needs to be protected during use, such as electroplating with gold, nickel, zinc, tin, and spraying epoxy resin on the surface.
NdFeB is divided into two types: sintered NdFeB and bonded NdFeB:
Bonded NdFeB magnets are magnetic in all directions and resistant to corrosion;
Since sintered NdFeB magnets are prone to corrosion, the surface needs to be plated. Generally, there are zinc plating, nickel plating, environmentally friendly zinc, environmentally friendly nickel, nickel copper nickel, environmentally friendly nickel copper nickel, etc. Sintered NdFeB is generally divided into axial magnetization and radial magnetization, which are determined according to the required working surface.
After a period of use of powerful NdFeB magnets, the originally smooth appearance will gradually develop white or other colored spots, which gradually widen and cause rust. Generally speaking, the coating of NdFeB magnets is not so easy to be rusted. , The damage caused by rust spots and corrosion on NdFeB magnets is mostly due to the following conditions:
1. The dirt on the surface of the NdFeB magnet is not completely cleaned before electrolysis;
2. The outer packaging plastic bag of NdFeB magnets is not well sealed, causing air oxidation of the magnets;
3. The duration of the electroplating process is not up to standard or there are technical problems;
4. The place where NdFeB magnets are stored has high humidity, poor indoor ventilation, and great changes in temperature.