News: Common Ferrite Preparation Methods

There are many methods for preparing ferrite, which are mainly divided into physical methods (such as oxide method, self-propagating high-temperature synthesis method, etc.) and chemical methods (such as chemical co-precipitation method, hydrothermal method, sol-gel method, etc.).
(1) Oxide method: The oxide method can also be called the ceramic method. This method generally uses Fe2O3, ZnO and other oxides as synthetic raw materials, mixes them well and then grinds and dries them fully before carrying out the molding process, and after molding, sintering them at a certain temperature to obtain ferrite. Currently, most of the factories in the market use this method to produce ferrite magnets, because of its simple process, abundant raw materials and low price. However, the ball milling process used in industrial production can easily introduce some impurities, which can deteriorate the performance of the finished product. In addition, because of the low reactivity of the oxide, a sintering temperature of more than 1000°C is required, which consumes more energy and leads to a lower quality of the finished product.
(2) Hydrothermal synthesis method: The hydrothermal synthesis method was originally inspired by the underground hydrothermal synthesis of minerals, and it is the most common method in the laboratory. The hydrothermal method refers to adding water to the reaction kettle and heating it to a certain temperature to generate high temperature and high pressure conditions, so that the reactants can undergo a series of chemical reactions to form nanoparticles. The ferrite powder obtained after heating the reaction kettle does not need to be sintered like other methods, so the growth of the product particles can be controlled to a certain extent, so that the ferrite product grains are fine and evenly dispersed. The heating temperature of this method is also much lower than other methods, and the operation process is relatively simple, but a series of reactions are carried out in the reaction kettle, which is not observable and cannot be operated and controlled in the intermediate process, and the amount of products obtained by hydrothermal method is very limited. Although the hydrothermal method can control the particle size to make the reaction more uniform, its results are influenced by many aspects and there are too many unpredictable factors.