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KNN-LS leadless piezoelectric ceramics and preparation method thereof

A lead-free piezoelectric and ceramic technology, applied in the field of lead-free piezoelectric ceramics with perovskite structure, can solve the problems of high equipment requirements, difficult industrial application, and generation of impurities, and achieve excellent electrical performance, good piezoelectricity, and stable properties. Effect

Active Publication Date: 2014-02-26
盐城市热威建材有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the traditional process to obtain KNN piezoelectric ceramics has the following disadvantages: (1) above 1140 ° C, KNN will appear in a liquid phase, so the temperature stability of KNN is limited below 1140 ° C
(2) Since Na and K will form oxide Na at around 900°C 2 O and K 2 The formation of O begins to volatilize, which makes it difficult to control the atmosphere of pre-firing and sintering; (3) KNN is very prone to deliquescence in a humid environment, which makes the stoichiometry deviate, resulting in the generation of impurity phases, making it difficult to sinter and compact ceramics
The above reasons limit the practical application of KNN system materials.
In order to optimize the structure of KNN-based lead-free piezoelectric ceramics and improve the piezoelectric performance of KNN-based ceramics, scholars from various countries have studied the KNN-based lead-free piezoelectric ceramics from the aspects of adding sintering aids, A-site and B-site doping substitution, and adding new components. A lot of research has been done on electric ceramics; at the same time, combined with hot pressing, discharge plasma, hot isostatic pressing sintering and other processes, in order to obtain dense KNN ceramics; however, the above preparation methods have high equipment requirements, harsh production processes, and high production costs , The size of the material is limited, and the stability of the prepared ceramics is not satisfactory, so it is difficult to obtain industrial applications

Method used

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  • KNN-LS leadless piezoelectric ceramics and preparation method thereof
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  • KNN-LS leadless piezoelectric ceramics and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0042] Step 1: KNbO synthesized by hydrothermal method 3 and NaNbO 3 Powder as raw material, according to 0.5KNbO 3 -0.5NaNbO 3 (x=0) stoichiometric ratio, calculate the required mass of each powder and weigh it to get the raw material.

[0043] Step 2: Put the raw materials weighed in step 1 into a beaker, add distilled water whose mass is 100% of the raw material mass, adopt the diffusion electric double layer principle mixing method, stir magnetically at room temperature for 1 hour until the mixture is uniform and form a colloid, and then put Put it into an oven at 80°C for drying to obtain a mixture;

[0044] Step 3: Add PVA solution of 5% of the mass of the mixture to the mixture obtained in step 2, wherein the mass concentration of the added PVA solution is 8%, mix well and put it in a dark environment for 24 hours, and then obtain by granulation Particles with good fluidity are then dry-pressed under a pressure of 200MPa to obtain a ceramic green sheet with a diamet...

Embodiment 2

[0049] Step 1: KNbO synthesized by hydrothermal method 3 , NaNbO 3 and LiSbO 3 Powder as raw material, according to 0.495KNbO 3 -0.495NaNbO 3 -0.01LiSbO 3 (x=0.01) stoichiometric ratio, calculate the required mass of each powder and weigh it to get the raw material.

[0050] Step 2: Put the raw materials weighed in step 1 into a beaker, add distilled water whose mass is 100% of the raw material mass, adopt the diffusion electric double layer principle mixing method, stir magnetically at room temperature for 1 hour until the mixture is uniform and form a colloid, and then put Put it into an oven at 80°C for drying to obtain a mixture;

[0051] Step 3: Add PVA solution of 5% of the mass of the mixture to the mixture obtained in step 2, wherein the mass concentration of the added PVA solution is 8%, mix well and put it in a dark environment for 24 hours, and then obtain by granulation Particles with good fluidity are then dry-pressed under a pressure of 200MPa to obtain a c...

Embodiment 3

[0056] Step 1: KNbO synthesized by hydrothermal method 3 , NaNbO 3 and LiSbO 3 Powder as raw material, according to 0.49KNbO 3 -0.49NaNbO 3 -0.02LiSbO 3 (x=0.02) stoichiometric ratio, calculate the required mass of each powder and weigh it to get the raw material.

[0057] Step 2: Put the raw materials weighed in step 1 into a beaker, add distilled water whose mass is 100% of the raw material mass, adopt the diffusion electric double layer principle mixing method, stir magnetically at room temperature for 1 hour until the mixture is uniform and form a colloid, and then put Put it into an oven at 80°C for drying to obtain a mixture;

[0058] Step 3: Add PVA solution of 5% of the mass of the mixture to the mixture obtained in step 2, wherein the mass concentration of the added PVA solution is 8%, mix well and put it in a dark environment for 24 hours, and then obtain by granulation Particles with good fluidity are then dry-pressed under a pressure of 200MPa to obtain a cer...

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Abstract

The invention discloses a KNN-LS leadless piezoelectric ceramics and preparation method thereof, and the chemical formula is (1-x)(0.5KNbO3-0.5NaNbO3)-xLiSbO3, x=0-0.09. KNbO3, NaNbO3 and LiSbO3 powder are used as raw materials, organic matter binder and water are added, and colloid is formed by stirring, and then the material is dried and the mixed material is obtained; water is added into the mixed material, after aging, dry-pressing and forming, the ceramic green compact pieces are obtained; the ceramic green compact pieces are treated by plastic discharging and are sintered at normal pressure for obtaining the KNN-LS leadless piezoelectric ceramics. The invention provides a leadless piezoelectric ceramics preparation method, which has the advantages of simple process, high efficiency, low energy consumption and low cost. The obtained KNN-LS leadless piezoelectric ceramics has the advantages of stabilization, compact and excellent electrical property.

Description

technical field [0001] The invention belongs to the field of lead-free piezoelectric ceramics with a perovskite structure, and relates to a KNN-LS lead-free piezoelectric ceramic and a preparation method thereof. Background technique [0002] Piezoelectric and ferroelectric ceramics are the most widely used types of functional ceramic materials, and are widely used in the fields of transducers, drivers, surface acoustic waves, filters, resonators, wave limiters and other frequency devices, including capacitor ceramics The piezoelectric and ferroelectric ceramics account for one-third of the entire functional ceramics in the world market share. [0003] In 1954, B.Jaffe in the United States discovered PbZrO 3 -PbTiO 3 (PZT) system, there is a temperature-independent phase transition in this system, and the piezoelectric performance shows an extreme value near the phase transition point. A series of new piezoelectric ceramic materials have been derived. However, since the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/622
Inventor 谈国强郝航飞
Owner 盐城市热威建材有限公司