Preparation method for tetragonal phase nano barium titanate

Abstract

The invention provides a preparation method for tetragonal phase nano barium titanate. The preparation method comprises the steps as follows: i), preparing water solutions of barium chloride and oxalic acid respectively, and mixing alcoholic solution of butyl titanate and oxalic acid solution uniformly to obtain titanium oxyoxalate complex ion solution; ii), adding titanium oxyoxalate complex ion solution obtained in the step i) into a supergravity reactor as a circulating flowing phase to control the supergravity level; and meanwhile, dropping barium chloride solution to obtain white barium titanyl oxalate precipitation suspension as a precursor of barium titanate, and keeping the pH value of the whole system at 2.5-3.5 during reaction; and iii),ageing the precipitation suspension obtained in the step ii), leaching, washing and drying to obtain white barium titanyl oxalate power. The preparation method provided by the invention has the advantages that tetragonal phase nano barium titanate can be prepared; and the particle size of the prepared power can be controlled to be within the range of 30-90 nm; the average particle size is small, and the particle size is narrow in distribution; and the degree of crystallinity is high, and the crystal formation is intact.

Description

technical field [0001] The invention relates to the field of inorganic nanometer materials, in particular to a preparation method of tetragonal nano barium titanate. Background technique [0002] In recent years, nanomaterials have become a research hotspot in current materials science due to their unique interface effects. Among them, barium titanate is a typical ferroelectric and dielectric material in the manufacture of nonlinear components such as dielectric amplifiers, ceramics Electronic components such as capacitors and ferroelectric devices have a wide range of important applications. The development of barium titanate powder began in the 1940s. At present, my country has introduced a number of multilayer ceramic capacitor (MLCC) production lines, and its dielectric material is mainly barium titanate. Since the thickness of each layer of a multilayer ceramic capacitor has reached about 3 μm, and each layer requires more than 5 layers of effective grain boundary laye...

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Problems solved by technology

[0005] Chinese patent CN1323759 discloses a preparation method of nano-scale tetragonal phase barium titanate powder, but the preparation method is a hydrothermal method, which requires high temperature and high pressure reaction conditions, which requires too high equipment, and the process is complicated and difficult to achieve continuous production

[0006] Chinese patent CN101746814A discloses a production process for preparing tetragonal phase barium titanate, but the preparation method is a hydrothermal method, which requires too much equipment, the process is complicated, and the produced product particles are relatively large, so it is impossible to produce titanium smaller than 100nm Barium Oxide Powder

[0007] Chinese patent CN102060325A discloses a preparation method of a tetragonal barium titanate nanorod array, but the obtained product is not a tetragonal barium titanate powder, and requires two-step hydrothermal reaction, the reaction conditions are complex, and the operation is cumbersome

[0008] Chinese patent CN102584215A discloses a method for preparing a graded porous tetragonal barium titanate ceramic material, but this method needs to prepare hollow nanospheres as a sintering precursor, the process is complicated and the calcination temperature is high, and the prepared product is a graded porous ceramic

[0013] In summary, it can be seen that the existing liquid-phase co-precipitation method and the classic solid-phase method cannot prepare high-purity, ultra-fine or even nano-scale tetragonal phase barium titanate powder, even if the tetragonal phase barium titanate powder is prepared, there are particles. Larger diameter, coarser particles, lower tetragonal ratio, or the method is not suitable for large-scale industrial production. Therefore, it is necessary to deepen the research on the preparation method of tetragonal phase nano-barium titanate, and seek more suitable for industrialization. Preparation technology and The technological conditions can really make the tetragonal phase nano barium titanate enter the era of industrial scale production

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