The principle of the electromagnet is relatively simple. It is the magnetic field generated by the energized spiral tube to form attraction. This is more used in our industry. For example, solenoid valves and relays are non-magnetic under normal conditions, or there is no attraction. Relying on electric energy to carry out transformation. The principle followed is the principle of conservation of energy, that is, how attractive you are, and you have to consume almost the same amount of electric energy. If you want to make the coil more attractive, you need to wind a few more turns of copper wire and current. And the voltage should also be increased.
But permanent magnets are different. Let's take a look at the composition of permanent magnets and how to make them. Permanent magnets are also called neodymium iron sheds. As the name suggests, they contain neodymium, iron, and boron. Boron is a chemical element cycle. The fourth element in the table is hydrogen, lithium, beryllium, and boron. How do these elements come together? This uses a process called powder metallurgy.
To put it simply, powder metallurgy is to grind various elements into powder separately, mix them according to a certain proportion, and stir them evenly, then put the mixed powder into a mold for extrusion molding, and then sinter after it is formed. Furnace sintering is similar to what we do for bricks. Because the sintering process has to go through a high-temperature furnace, it will inevitably produce more serious deformations. After that, several working surfaces must be water-milled. The magnet at this time, I can't call it a complete magnet. At this time, its name is soft magnet. For example, the ceramic tile in the motor is in this state. Anyone who has dismantled the motor should know the magnetic tile in the motor. You can't suck things. If you have a lot of things, just use this, and the public welfare will end here. But this is not the case with neodymium iron sheds. At this time, electricity is used to magnetize. Strictly speaking, it is a process of magnetization. It is short-circuited from one side of the magnet to the other through a certain strong instantaneous current. The sintered soft magnetic inner band and certain conductive material, after being magnetized by a strong current, becomes a permanent magnet.