The thermal expansion of rare earth permanent magnets and the 20mm diameter neodymium iron boron strong magnetic tension and Gauss value data reference
The thermal expansion and magnetostriction of rare earth permanent magnets will cause the size of the magnet to change to different degrees. If the thermal expansion and contraction of other assembly materials in the magnetic assembly are quite different, this size change will cause a certain stress to the magnet. It may cause mechanical damage or deterioration of the magnet. In the application of large-scale permanent magnet materials, thermal expansion and magnetostriction phenomena need to be given full attention.
Conventional metal and non-metal materials have positive linear expansion coefficients, so there are often sayings of thermal expansion and contraction. For example, the linear expansion coefficients of steel, copper and aluminum are 12 x 10-6/℃, 17 x -6/℃ and 24 x -6/℃. The coefficient of linear expansion of sintered ferrite and sintered samarium-cobalt magnet is within the range of (10~15) x 10-6/℃, which is very close to steel. Therefore, when these two magnets are assembled with iron yoke to produce magnetic components, No need to worry about mismatch caused by thermal expansion. However, the strong magnetocrystalline anisotropy of SmCo and ferrite will cause the thermal expansion coefficient of the sintered magnet that needs to be oriented to also have anisotropy, which is a phenomenon that needs to be considered in the preparation and application of the magnet.
The thermal expansion and contraction behavior of neodymium iron boron magnets is even more strange. At lower than the Curie temperature, the main phase Nd2Fe14B has obvious Invar effect, and the linear expansion coefficient perpendicular to its c-axis is negative, parallel to The linear expansion coefficient in the c-axis direction returns to a positive value after about 70°C lower than the Curie temperature, and the average value of the linear expansion coefficient is 1 x 10-6/°C.
The abnormal thermal expansion of neodymium iron boron magnets stems from the 3d electronic magnetic characteristics of iron atoms. For example, if the magnet is assembled with other materials into magnetic components by bonding, the mismatch during assembly and use is more serious.
20mm diameter neodymium iron boron strong magnetic tension and Gauss value data reference
The 0mm rare earth magnet is a commonly used specification in the market. The shape is mostly round, square, ring, and counterbore. Many customers often inquire about a 20mm diameter round magnet and ask about its attractive force. How many Gauss (gauss), today I have compiled some 20mm magnet tension and Gauss value data for your reference.
Test qualified by jinluncicai.com - rare earth permanent magnet manufacturer and factory.
The following data is for reference only and is subject to actual measurement. Different Gauss meters have different measurement methods and different values of magnetization direction.
Tensile force and Gauss value of a circular magnet with a diameter of 20mm;
N50 performance/D20x1mm: Its magnetic flux reading is 721 Gauss, and its pulling force is 1.44 kg.
N42/20mmx2mm: tensile force is 2.6kg, Gauss value is 1060gs, sliding resistance: 0.5kg
N42/D20*5: Vertical tension is about 7.2kg, sliding resistance: 1.46kg, magnetic field strength is 3200gs.
D20*10mm, N52 performance, surface magnetism is 4600gs, tensile force is 14.8kg.
N42 grade D20*20mm strong magnet: the surface magnetism is 5500gs, and the tensile force is about 15kg.
N35/NI/F20*6*1.5, Gauss is about 1600gs.
N42/nickel/20x20x5mm, the Gauss value is about 2520gs, and the vertical tension is about 7.8kg. A magnet with the same length and width, the thickness of 10mm is about 4050gs, and it cannot reach more than 5000gs