China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Here we go, here we go, here we go again. Today, we will continue to introduce issues related to the surface magnetic field of magnets. Some customers have inquired why the maximum surface magnetic field of an N52 grade magnet with dimensions 4*4*0.8 is lower than that of an N52 magnet with dimensions 4*3.2*0.8. Many netizens likely assume that the former has a higher surface magnetic field. Let's briefly explain this.
Not just this customer, many people believe that under the same material conditions, the larger the size of the magnet, the higher its maximum surface magnetic field will be. However, this is not actually the case. The surface magnetic field of a magnet is actually inversely proportional to its area, meaning that the larger the specification, the smaller the surface magnetic field value will be.
The primary reason lies in the differing Pc values of the two, which are caused by their respective demagnetization fields. Since the 4*4*0.8mm magnet has a larger demagnetization field, its maximum surface magnetic field will be lower. The corresponding operating point and demagnetization curve are shown in the figure below.
n52 grade 4x4x0.8mm BH curve
n52 grade 4x3.2x0.8mm BH curve
The above is a brief introduction regarding the fact that the magnetic specification F4*4*0.8 has a lower surface magnetic ratio compared to F4*3.2*0.8. If you have any magnet purchasing needs, please provide us with relevant information.
Magnet with a thickness of 0.8mm on the website;
1 inch thin disc magnets with 3M self adhesive 25mm x 0.8mm