A two-step hydrothermal method for the synthesis of lead-free piezoelectric ceramic k 0.65 na 0.35 nbo 3 powder method

Abstract

The invention provides a two-step hydrothermal synthesis of lead-free piezoelectric ceramics K 0.65 Na 0.35 NbO 3 In the powder method, excess potassium hydroxide and sodium hydroxide are respectively used as potassium source and sodium source, dissolved in deionized water; 3 , NaNbO 3 The precursor solution; after the precursor solution is sealed in a hydrothermal kettle, put it into a constant temperature box for hydrothermal synthesis at a certain temperature, after the reaction is completed and cooled to room temperature, the powder obtained by the reaction is washed several times with deionized water, Finally dry. After grinding process, accurately weigh KNbO 3 , NaNbO 3 The powder is mixed in deionized water; after stirring, it is shaken by microwave; it is poured into a hydrothermal reaction kettle and sealed for hydrothermal synthesis. After the reaction is completed, it is cooled to room temperature, and the resulting mixed solution is fully dried to obtain a powder. Adopt two-step hydrothermal method to synthesize K among the present invention 0.65 Na 0.35 NbO 3 Powder, the preparation process has good repeatability, the material composition ratio is accurate, the powder has good uniformity, high purity, complete grain development and uniform distribution.

Description

technical field [0001] The invention relates to the field of piezoelectric ceramic powder preparation, in particular to a two-step hydrothermal synthesis of lead-free piezoelectric ceramic K 0.65 Na 0.35 NbO 3 powder method. Background technique [0002] The currently used piezoelectric ceramic material is lead zirconate titanate, wherein lead oxide in the lead-based piezoelectric ceramic accounts for about 70% of the total weight of the raw material. Since lead oxide is a volatile toxic substance, it will cause serious harm to humans and the ecological environment during use and disposal; at the same time, it needs to be sealed and sintered during the preparation process, which not only increases the cost of the product, but also causes damage to the product. performance consistency is poor. With the implementation of the social sustainable development strategy and the enhancement of people's awareness of environmental protection, the research and application of lead-fr...

AI Technical Summary

Problems solved by technology

For this purpose, chemical precipitation method and sol-gel method have been adopted successively. The above methods are either complicated in operation, or complex in process, long in cycle and poor in repeatability.

In contrast, the hydrothermal method has certain advantages in the synthesis of potassium sodium niobate, so it is the method adopted by most researchers, but the traditional hydrothermal method cannot avoid problems: because the binding abilities of K and Na ions to Nb are too different Large, if synthesized by the traditional one-step hydrothermal method, often (K, Na)NbO 3 The existence of K cannot be reflected in the powder at all; but the use of NaNbO 3 , KNbO 3 Separate synthesis and then mix, if mixed during washing, (K,Na)NbO 3 The ratio of potassium to sodium cannot be accurately controlled at all; if the prepared NaNbO 3 , KNbO 3 Powder weighing and mixing, although accurate potassium and sodium ratios can be guaranteed, but the uniformity after mixing will not be guaranteed

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