Method for preparing potassium-sodium niobate textured ceramic and potassium-sodium niobate single crystal

A technology of potassium sodium niobate and ceramics, which is applied in the field of preparation of potassium sodium niobate textured ceramics and potassium sodium niobate single crystal, which can solve problems such as difficulties, precise control, and piezoelectric performance degradation

Inactive Publication Date: 2010-12-15
GUILIN UNIV OF ELECTRONIC TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although it is generally believed that the preparation of textured piezoelectric ceramics by the template grain growth method can greatly improve the piezoelectric properties of ceramics, there are still many problems in this method that have not been completely resolved. It is difficult to arrange uniformly and equidistantly in the sample; (2) it is difficult to accurately control the uniform orientation and uniform distribution of the template in the green body; (3) it is difficult to control the rapid directional growth of matrix particles on the template; ( 4) The introduction of a large number of template grains, especially the introduction of heterogeneous templates, will form a large-grain composite material, which will cause a mismatch in lattice, elastic properties, and thermal properties, resulting in a decrease in piezoelectric properties (Reference : Sui Wanmei. Preparation method of polycrystalline texture ceramic material. China, invention patent, publication number: CN1850725A, 2006.10.25.)

Method used

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  • Method for preparing potassium-sodium niobate textured ceramic and potassium-sodium niobate single crystal
  • Method for preparing potassium-sodium niobate textured ceramic and potassium-sodium niobate single crystal
  • Method for preparing potassium-sodium niobate textured ceramic and potassium-sodium niobate single crystal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Take Na 2 CO 3 、K 2 CO 3 , Nb 2 o 5 , Li 2 CO 3 and Bi 2 o 3 As a raw material, according to the chemical formula:

[0019] 0.996 (K 0.5 Na 0.5 )NbO 3 -0.004LiBiO 3

[0020] Carry out batching, wet mill with absolute ethanol as the medium for 12 hours, dry and keep warm at 880°C for 6 hours to pre-synthesize porcelain material; Compressed under pressure to φ18×2mm 2 Biscuit sample.

[0021] The green sample was placed horizontally in a high-temperature electric furnace, held at 500°C for 2 hours to debinding, and finally sintered at 1125°C for 3 hours to obtain sintered ceramics. Microstructural analysis shows that the ceramics have obvious directional growth characteristics, complete crystal form and clear texture. figure 1 and figure 2 Shown are the natural surface SEM photographs and cross-sectional XRD patterns of the samples prepared in Example 1, respectively.

Embodiment 2

[0023] Take Na 2 CO 3 、K 2 CO 3 , Nb 2 o 5 , Li 2 CO 3 and Bi 2 o 3 As a raw material, according to the chemical formula:

[0024] 0.996 (K 0.5 Na 0.5 )NbO 3 -0.005LiBiO 3

[0025]Carry out batching, wet mill with absolute ethanol as the medium for 12 hours, dry and keep warm at 880°C for 6 hours to pre-synthesize porcelain material; Compressed under pressure to φ18×2mm 2 Biscuit sample.

[0026] The green body sample was placed horizontally in a high-temperature electric furnace, held at 500°C for 2 hours to debinding, and finally sintered at 1125°C for 12 hours to obtain sintered ceramics. Microstructural analysis showed that larger single-crystal grains with a size of about 2 mm grew out of the ceramic. image 3 Shown is the SEM photo of the single crystal prepared in Example 2.

Embodiment 3

[0028] Take Na 2 CO 3 、K 2 CO 3 , Nb 2 o 5 , Li 2 CO 3 and Bi 2 o 3 As a raw material, according to the chemical formula:

[0029] 0.996 (K 0.5 Na 0.5 )NbO 3 -0.005LiBiO 3

[0030] Carry out batching, wet mill with absolute ethanol as the medium for 12 hours, dry and keep warm at 880°C for 6 hours to pre-synthesize porcelain material; Compressed under pressure to φ18×2mm 2 Biscuit sample.

[0031] The biscuit sample was placed horizontally in a high-temperature electric furnace, held at 500°C for 2 hours to remove the glue, and finally sintered at 1115°C for 10 hours to obtain a sintered ceramic. Microstructural analysis shows that the ceramics have significant directional growth characteristics, and the ceramics are dense and the single crystal particle size is about 1-2mm.

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Abstract

The invention aims to provide a method for preparing potassium-sodium niobate textured ceramic and potassium-sodium niobate single crystal. K0.5Na0.5NbO3 is used as a main material and LiBiO3 or BiNiO3 is used as a doping raw material; and the method comprises the following steps of: performing wet-milling on the materials by using anhydrous alcohol as a medium and drying the materials to synthesize a ceramic material; performing secondary ball milling on the ceramic material, drying the ceramic material and adding an adhesive into the ceramic material to granulate; pressing the mixture under the pressure of 110MPa to prepare a biscuit sample; horizontally placing the biscuit sample into a high temperature electric furnace for sintering; and cooling the sintered biscuit sample along with the furnace to the room temperature so as to prepare KNN-based ceramic, wherein the single crystal with size of over 2mm can also be obtained by controlling the sintering temperature and the sintering time. By using the conventional ceramic preparation process, the KNN ceramic with superior preferred orientation is prepared under normal conditions; and the single crystal with size of over 2mm can also be obtained by controlling the sintering temperature and the sintering time.

Description

technical field [0001] The invention relates to a lead-free piezoelectric ceramic material, in particular to a preparation method of potassium sodium niobate textured ceramics and potassium sodium niobate single crystal. Background technique [0002] PbZrO composed of ferroelectric and antiferroelectric 3 -PbTiO 3 Lead-based piezoelectric ceramics represented by (PZT) solid solution system are widely used in the fields of transducers, drivers and resonators. Since the toxic lead oxide content in PZT series ceramics exceeds 60% of the total mass of raw materials, it has brought serious harm to the living environment of human beings. The lead-free piezoelectric ceramics is an urgent hope for human development. Compared with other lead-free piezoelectric ceramics currently studied, potassium sodium niobate (K 0.5 Na 0.5 NbO 3 , KNN) piezoelectric ceramics are considered to be promising lead-free alternatives to PZT because of their small dielectric constant, high piezoelec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/622C30B29/30
Inventor 江民红邓满姣刘心宇陈国华徐华蕊刘超英
Owner GUILIN UNIV OF ELECTRONIC TECH
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