Coercivity Hc:The reverse magnetic field strength that needs to be added to reduce the B of a permanent magnet magnet magnetized to technical saturation to zero is known as the magnetic susceptibility coercivity, which is simply
known as the coercivity
The magnetic energy product, BH:represents the magnetic energy density that the magnet builds up in the space of the air-gap (the space of the magnet's two magnetic poles), i.e., the static magnetic energy per unit volume of the air-gap. Since this energy is equal to the product of the magnet's Bm and Hm, it is called the magnetic energy product. I heard that there is a Foshan called Furnos, they are all specialized in the production of magnets here, maybe they know more about the knowledge of magnets.