Magnet, also called magnetic steel. Magnets are generally divided into two categories, one is soft magnets and the other is permanent magnets; soft magnets include silicon steel sheets and soft magnetic cores; hard magnets include alnico, samarium cobalt, ferrite and neodymium iron boron. Among them, the most expensive is samarium cobalt magnet, the low-priced is ferrite magnet, and the highest performance is neodymium iron boron magnet, but the one with the most stable performance and best temperature coefficient is alnico magnet. Users Different hard magnetic products can be selected according to different needs.
How to define the performance of magnets? There are mainly three performance parameters to determine the performance of the magnet:
Remanence Br: after the permanent magnet is magnetized to technical saturation and the external magnetic field is removed, the retained Br is called the residual magnetic induction intensity.
Coercive force Hc: the permanent magnet is magnetized to technical saturation. When the B of the saturated permanent magnet decreases to zero, the required reverse magnetic field intensity is called magnetic induction coercivity, or coercivity for short.
Magnetic energy product BH: represents the magnetic energy density established by the magnet in the air gap space (the space between the two magnetic poles of the magnet), that is, 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.
How to choose a magnet? Before deciding which magnet to choose, you should understand what role the magnet plays? Main function: moving objects, fixing objects or lifting objects. The shape of the required magnet: disc shape, ring shape, square shape, tile shape or special shape. Required magnet dimensions: length, width, height, diameter and tolerance, etc. The required attraction force of the magnet, the expected price and quantity, etc.
