Nickel-Zinc Ferrites Prepared By Sol-Gel Method

As a kind of important nonmetallic magnetic materials, ferrites are used a lot in our life. Since they were discovered, people do extensive studies on them. The synthesis of the powder has always been the main subject. Besides the traditional synthesis, there are many new methods, such as hydrothermal method, microemulsion method and co-precipitation method. But because of the disadvantage of these methods, they have not been applied in industry. During these years, With the development of the miniaturization and lightness of electronic devices and the electro-magnetic properties of ferrite materials are also expected to satisfy the high permeability, high limited frequency, wide frequency range and low power loss, conventional synthesis can not satisfy the demands of people.Nickel-Zinc ferrites with spinel structure (AB₂O₄) are a kind of polynary metal oxide sintered materials. They have been playing an important role in the application of high frequency field of magneto-electronic devices since they were discovered. Apart from these demands for permeability and frequency, more must be done to improve the technics of production, especially on how to reduce the consumption of energy. So, it is very important for the society, especially for the development of electronics and information industry to study and develop a new method to produce high permeability, high limiting frequency and wide frequency range materials with low energy consumption.This thesis contains five chapters. The main contents are as follows:The first chapter mainly summarizes the current development of soft magnetic ferrite materials, and gives the reason that why we choose the sol-gel method to synthesize the Nickel-Zinc ferrites.The second chapter is the seedtime, generally presents the basic theory of ferrites with spinel structure, including the origin of magnetism, the crystal structure of spinel-type ferrites, and some parameters of soft magnetic materials. At last enumerates and analyzes some familiar methods used in ferrite preparation.The third chapter presents the method of preparation and measurement in this thesis, and simply describing raw materials, process flow, instrument and measurement.The fourth chapter shows the experiment results and theoretic analysis. It is the main chapter of this thesis. In this chapter we have seriously described and analyzed the results and then give the conclusion.The last chapter summarizes this thesis and look forward to the use prospect of sol-gel method.