In the external magnetic field, materials can show three situations: ① those that are not attracted by the magnetic field are called diamagnetic materials; ② Those weakly attracted by the magnetic field are called paramagnetic materials; ③ The ferromagnetic material is strongly attracted by the magnetic field. Its magnetism increases sharply with the strengthening of the external magnetic field, and can still retain its magnetism after the external magnetic field is removed. In metal materials, most transition metals have paramagnetism; Only a few metals such as Fe, Co and Ni are ferromagnetic.
The main elements of permanent magnetic materials in metals are Fe, Co, Ni and some rare earth elements. Are there rare earths in the permanent magnet alloy used? Cobalt series, iron? Chromium? Cobalt series and manganese? aluminium Carbon alloy.
Magnetic alloys have been widely used in power, electronics, computers, automatic control and electro optics.
