Method for preparing potassium niobate nano powder

Abstract

The invention relates to a method for preparing potassium niobate nano powder. The single-phase nano KNbO3 powder can be obtained at a low temperature by the method. The method comprises the following steps of: mixing potassium hydroxide and niobium pentaoxide in a molar ratio of 8-12:1, calcining the mixture for 1 to 4 hours at the temperature of between 320 and 400 DEG C, dissolving the obtained solid into deionized water, adding oxalic acid, regulating the pH value of the solution to between 4 and 5, and obtaining white sediment; dissolving the white sediment into aqueous solution of citric acid, adding potassium nitrate according to the component proportion of KNbO3, and obtaining a precursor by sol-gel and burning processes; and calcining the precursor at the temperature of between 600 and 800 DEG C to obtain the potassium niobate powder with grain diameter of between 10 and 70 nanometers and with perovskite structure. The process is simple and quick, the prepared powder has high purity and low granularity, and the cost is reduced.

Description

technical field [0001] The invention relates to a preparation method of potassium niobate nano powder, specifically preparing nano potassium niobate powder through the preparation of hydrated niobium oxide and the combination of sol-gel and combustion synthesis, which belongs to the field of fine chemical industry. Background technique [0002] Potassium niobate (KNbO 3 ) is a ferroelectric oxide with perovskite type, which has good electro-optic coefficient and nonlinear optical coefficient, and is widely used in the fields of laser frequency doubling and photorefraction. KNbO has been discovered in recent years 3 It has excellent piezoelectric properties and has broad application prospects in surface acoustic waves and transducer devices. In addition, KNbO 3 It is also commonly used in the field of photocatalysis. [0003] Potassium Niobate KNbO 3 The synthesis of powder usually adopts the method of solid state reaction, and the mixed Nb 2 o 5 and K 2 CO 3 The pow...

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Problems solved by technology

However, most of the potassium hydroxide does not participate in the reaction in this method, resulting in a waste of raw materials. Secondly, the reaction is carried out under high temperature and high pressure, which requires higher requirements for equipment.

The sol-gel method can also prepare niobate powder. The key to this method is the selection of niobium source. Because organic alkoxide has good solubility, it is often used as the niobium source of sol-gel method, but the organic alcohol The price of salt is expensive, and the use environment is strict, which is not conducive to the promotion of industrialization

Li Yao's "Preparation of Potassium Lithium Niobate Nanopowder by Citric Acid Gel Method" (patent number: 200410043777.2) uses hydrated niobium oxide as the niobium source, and prepares potassium lithium niobate powder by sol-gel method. This method The prepared potassium lithium niobate powder is relatively fine, but this method uses HF to dissolve Nb 2 o 5 Fluoride ions are likely to remain in the prepared soluble niobium salt, resulting in residual fluoride ions in the final niobate powder, which reduces the photoelectric performance of the powder

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