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 method for synthesizing lead-free piezoelectric ceramic K0.65Na0.35NbO3 powder. Excess potassium hydroxide and sodium hydroxide are used as potassium source and sodium source respectively, and are dissolved in deionized water. ; Then add niobium pentoxide to the solution and stir evenly to synthesize the precursor liquids of KNbO3 and NaNbO3 respectively; seal the precursor liquids in hydrothermal kettles and put them into a constant temperature box for hydrothermal synthesis at a certain temperature. After the reaction was completed, it was cooled to room temperature, and the powder obtained by the reaction was washed several times with deionized water and finally dried. After the grinding process, the KNbO3 and NaNbO3 powders are accurately weighed and mixed in deionized water; stir and then use microwave vibration; pour into the hydrothermal reaction kettle and seal for hydrothermal synthesis. After the reaction is completed, cool to room temperature and complete the reaction. The resulting mixed liquid is fully dried to obtain powder. In the present invention, a two-step hydrothermal method is used to synthesize K0.65Na0.35NbO3 powder. The preparation process has good repeatability, the material component ratio is accurate, the powder uniformity is good, the purity is high, and the crystal grains are fully developed and evenly distributed.

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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