The frequency of using magnets is still relatively high. I don't know if you have any bubbling phenomenon, because in life, we are not working, there are many problems we may not be able to meet. After the foaming of magnets, it will definitely affect our use effect. Then, the problems that cause the problems of magnets are generally those that occur during the production. Let's understand the causes of the foaming of magnets?
① For example, when the difference of moisture content between the inside and outside of the blank is large, the magnet will simply bubble. This is because the initial external water transpiration speed of the blank is faster than the internal water dispersion speed. With the passage of time, the external water content decreases, and the difference between the internal and external water content of the blank increases. If there is residual closed water in the blank base, it will bubble at high temperature. If the water content difference between the inside and outside of the blank, it will be gradually reduced, and the foaming will also be gradually reduced.
② In the second fine grinding, the larger the particle size, the simpler the internal and external capillary water dispersion, and the smaller the foaming rate of the magnet.
③ When sintering, there is no foaming below a certain sintering temperature, which is called the critical temperature of foaming. Beyond this temperature, the foaming rate will gradually improve with the progress of sintering temperature. With the advance of pre firing temperature, the critical temperature of foaming is also improved.
④ Another reason for bubbling is that after the iron mixed with the pre burned material due to crushing and grinding in the crushing technology generates Fe2O3, it will be differentiated according to the reaction formula of 6fe203 = 4fe304 + o22fe2o3 = 4feo + O2 during sintering. When this Fe2O3 is violently reduced to FeO, if the differentiated O2 cannot be discharged, it will also make the blank bubbling.
⑤ The magnets of sintering furnace with good ventilation are easy to produce bubbles.