Neodymium Disc Magnet
Neodymium disc magnet or disk magnet is the thin circular Neo magnet with the thickness smaller than its diameter. It is the most commonly used magnet shape to meet the most versatile application requirement, such as sensors, loudspeakers and even high speed electric motors, etc. It is often encased by the steel to work as holding application through round base magnets, magnetic push pins, hook magnets, etc. The round shaped disc magnet is also named as disc Neodymium magnet, NdFeB disc magnet, Neo disc magnet, and so on.
Most disc magnets are axially magnetized, that’s to say the magnetic north pole and south pole on the two largest sides of the disc magnet. The Neodymium disc magnet can be produced by round shaped cylinder magnet blocks or rectangle shaped magnet blocks. If the diameter is big for example D50 mm, it’s easy to press a rough long cylinder and machine through simple coreless grinding and inner circle slicing to many pieces of thin disc shape with good appearance, size, etc. If the diameter is small, for example D5 mm, it’s not economic to press a cylinder. And then we may consider pressing a big block magnet, and then machine through slicing it to many pieces of small block magnets, rolling the block magnets to cylinders, coreless grinding and inner circle slicing. The reason for using this production method for disc magnets with small diameter is that machining cost is lower than pressing a small cylinder directly.
Because Neodymium magnet is easy to corrode or oxidize, the Neodymium disc magnet must need surface treatment. The most common coating for Neodymium magnets is three layers of NiCuNi (Nickel + Copper + Nickel). This NiCuNi plating offers the Neodymium magnets relatively good protection from corrosion and passive applications. If the Neo magnet will be exposed to moisture or liquid, an organic coating such as epoxy might be a good choice. Moreover, epoxy is suitable for applications with disc Neodymium magnets under some friction or knocking.
In Germany, France, US, Brazil and many East Europe, some companies sell magnets via Amazon and list many standard dimensions of Neodymium disc magnets, and some of the best selling sizes are below:
|D1 x 1||D9 x 5||D12 x 4||D15 x 5||D20 x 5|
|D2 x 1||D10 x 1||D12 x 4||D15 x 8||D20 x 7|
|D3 x 1||D10 x 1.5||D12 x 5||D15 x 15||D20 x 10|
|D4 x 2||D10 x 4||D12 x 6||D16 x 4||D25 x 3|
|D6 x3||D10 x 5||D12 x 10||D18 x 3||D25 x 7|
|D8 x 1||D10 x 10||D15 x 1||D18 x 4||D30 x 10|
|D8 x 2||D11 x 1||D15 x 2||D18 x 5||D35 x 5|
|D8 x 3||D12 x 1||D15 x 3||D20 x 2||D35 x 20|
|D8 x 5||D12 x 2||D15 x 3||D20 x 3||D45 x 15|
|D9 x 3||D12 x 3||D15 x 5||D20 x 3||D60 x 5|