Method for preparing bismuth ferrite powder by microwave hydrothermal method

Abstract

The invention discloses a method for preparing bismuth ferrite powder by microwave hydrothermal method, comprising: (1) dissolving FeCl3.6H2O and Bi(NO3)3.5H2O in proper amount of glycol to prepare into a parent salt solution; (2) dripping the parent salt solution into an aqueous ammonia solution with the concentration being 0.1-0.5mol / l and dripping speed being less than 2ml / min, and after finishing dripping, continuing to stir for 0.4-1h to obtain a deposit; (3) washing the deposit with de-ionized water repeatedly, ageing, and preparing a hydrothermal reaction precursor; and (4) adding the precursor solution into a microwave hydrothermal reaction kettle with the filling ratio being 60-75%, adding a mineralizer into the reaction kettle, placing the reaction kettle into a microwave assistant hydrothermal synthesizer to react for certain period, taking out a product in the reaction kettle, washing with de-ionized water to obtain a neutral product, washing the neutral product with absolute ethanol, and drying at room temperature to obtain the bismuth ferrite powder. The invention has the advantages of complete crystallization of BiFeO3, uniform grain fineness distribution, simple technical control, short technical cycle and energy saving.

Description

Technical field: [0001] The invention relates to a preparation method of bismuth ferrite powder, in particular to a method for preparing bismuth ferrite powder by a microwave hydrothermal method. Background technique: [0002] In recent years, ferromagnetoelectric materials have aroused great interest. It has both ferroelectricity and ferromagnetism. It can be induced by an electric field to generate a magnetic field. At the same time, a magnetic field can also induce electrical polarization. It has extremely important application prospects in spintronic devices, magnetic sensors and capacitive-inductive integrated devices. As a typical single-phase ferroelectric material, BiFeO 3 It has a high ferroelectric Curie temperature (T c -1103K) and magnetic transition temperature (T N -643K), is one of the very few materials that have a magnetoelectric coupling effect above room temperature. [0003] Currently, the synthesis of BiFeO 3 The methods of powder mainly include hig...

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Problems solved by technology

The above methods are often difficult to obtain pure phase BiFeO 3 , especially the high-temperature solid-phase method, after sintering, it is necessary to remove Bi with the help of nitric acid 2 Fe 4 o 9 and Bi 25 FeO 40 Such impurity phases make the surface of the powder rough, and the repeatability of the experiment is not good. At the same time, the synthesis temperature of the above method is high, often close to or even higher than the Curie temperature, which ultimately affects the ferroelectric properties of the material; the ordinary hydrothermal synthesis method It can be carried out at a lower temperature, and the obtained powder has good crystallization and dispersion properties, and under suitable conditions, a pure phase of BiFeO can be obtained 3 , but the conventional hydrothermal method to prepare powder has a long reaction cycle and the reaction process is not easy to control

[0004] So far, there is no domestic preparation of BiFeO by microwave hydrothermal 3 There are few reports on powders abroad. J.Prado-Gonjal et al. directly use solid raw materials as reactants, and compare the preparation of BiFeO by ordinary hydrothermal, microwave solid-phase method and the combination of the two. 3 Powder, BiFeO is prepared by a combination of the two 3 It only takes 30min, and the prepared BiFeO 3 There are very few powder impurity phases, but the disadvantage of this method is that the direct use of solid raw materials is likely to cause uneven concentration, resulting in uneven particle size of the synthesized powder, and the use of co-precipitation method to prepare precursors can avoid uneven concentration, thus obtaining Particles with uniform particle size and narrow particle size distribution

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