Method and equipment for synthesizing lithium tantalite doped potassium sodium niobate ceramic

A technology of potassium sodium niobate and synthesis method, which is applied in the field of functional ceramics, can solve the problems of reducing the activation energy of the reaction and not conforming to environmental protection, and achieves excellent electromechanical performance, good commercial value, and the effect of solving environmental loads

Inactive Publication Date: 2011-09-07
SHANGHAI MARITIME UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] After searching the literature of the existing technology, it was found that Wang Nian of Wuhan University of Technology published a master's degree thesis "Powder Synthesis of PLZT and Research on Microwave Sintering Process", specifically using the rapid sintering of microwaves to reduce the reaction activation energy and promote the grain boundary. Diffusion, which helps to obtain high-density lanthanum-doped lead zirconate titanate (PLZT) piezoelectric ceramics, but PLZT is a lead-containing piezoelectric ceramic, which does not meet the requirements of environmental protection

Method used

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  • Method and equipment for synthesizing lithium tantalite doped potassium sodium niobate ceramic
  • Method and equipment for synthesizing lithium tantalite doped potassium sodium niobate ceramic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The compounding ratio (mole percentage) of three components is: 10% of lithium tantalate, 45% of potassium niobate, and 45% of sodium niobate. Ball milling and mixing, adding 5% polyvinyl alcohol (PVA) to granulate, and dry pressing under 200Mpa pressure to make green body. Under the condition of 450°C for 5 hours, the viscous body was debonded, and the debonded sample was loaded into a multi-mode resonant cavity microwave sintering equipment. The first step is rapid heating, the heating rate is 20°C / min, and the temperature is raised to 1100°C for 3 minutes; the second step is rapid cooling, the cooling rate is 40°C / min, down to 950°C, and the heat preservation is 45min.

[0025] The electromechanical performance is: d 33 =255PC / N,k P =0.51,Q m =450,ε 33 T / ε 0 = 808, tan δ = 0.005.

Embodiment 2

[0027] The compounding ratio (mole percentage) of three components is: 10% of lithium tantalate, 45% of potassium niobate, and 45% of sodium niobate. Ball milling and mixing, adding 5% polyvinyl alcohol (PVA) to granulate, and dry pressing under 200Mpa pressure to make green body. Under the condition of 450°C for 5 hours, the viscous body was debonded, and the debonded sample was loaded into a multi-mode resonant cavity microwave sintering equipment. The first step is rapid heating, the heating rate is 20°C / min, and the temperature is raised to 1100°C for 3 minutes; the second step is rapid cooling, the cooling rate is 40°C / min, down to 1000°C, and the heat preservation is 90 minutes.

[0028] The electromechanical properties are: :D 33 =268PC / N,k P =0.52, Q m =380,ε 33 T / ε 0 = 870, tan δ = 0.008.

Embodiment 3

[0030] The compounding ratio (mole percentage) of three components is: 10% of lithium tantalate, 45% of potassium niobate, and 45% of sodium niobate. Ball milling and mixing, adding 5% polyvinyl alcohol (PVA) to granulate, and dry pressing under 200Mpa pressure to make green body. Under the condition of 450°C for 5 hours, the viscous body was debonded, and the debonded sample was loaded into a multi-mode resonant cavity microwave sintering equipment. The first step is rapid heating, the heating rate is 20°C / min, and the temperature is raised to 1150°C for 1 minute; the second step is rapid cooling, the cooling rate is 40°C / min, down to 950°C, and the heat preservation is 90min.

[0031] The electromechanical performance is: d 33 =283PC / N,k P =0.53, Q m =320,ε 33 T / ε 0 = 896, tan δ = 0.011.

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Abstract

The invention provides a method for synthesizing lithium tantalite doped potassium sodium niobate ceramic. The method comprises the following steps of: ball-milling and mixing 5 to 15 molar percent of lithium tantalite, 42.5 to 47.5 percent of potassium niobate, and 42.5 to 47.5 molar percent of sodium niobate, adding 5 percent polyvinyl alcohol (PVA) and pelleting, and performing dry pressing and forming under the pressure of 200 MPa to obtain green blank; preserving heat at the temperature of 450 DEG C for 5 hours and removing adhesion of the green blank, filling a sample which is subjected to adhesion removal into multimode cavity microwave sintering equipment and sintering; and polishing the sintered sample to form a wafer with a diameter of 10 to 11mm and thickness of 0.5mm, coating silver, and then applying voltage of 3 to 4KV/mm in silicone oil at the temperature of 120 DEG C and polarizing for 30 minutes. In the method, the multimode cavity microwave sintering equipment is adopted, the sample is placed in a self-developed chromic acid lanthanum inlayer heat preservation body, zirconium oxide fiber is filled between the sample and the heat preservation body, and the heat preservation body of an outer layer has a corundum structure. The lithium tantalite doped potassium sodium niobate ceramic prepared by the method has the excellent electromechanical properties and lead pollution is avoided.

Description

technical field [0001] The invention relates to the field of functional ceramics, in particular to a two-step microwave sintering method for lead-free piezoelectric ceramics doped with lithium tantalate and potassium sodium niobate, and also relates to a device for synthesizing the ceramics. Background technique [0002] The microwave sintering method used in the preparation of ceramics has attracted widespread attention. It is different from the conventional solid-state sintering method, especially in the application of functional ceramics, which has obvious advantages in improving material properties. Since the discovery of lead zirconate titanate Pb(Ti,Zr)O in the 1950s 3 Since (PZT) piezoelectric ceramics, the main component of practical piezoelectric ceramics is PbO, and the lead content is as high as 60%. Lead-based ceramics have caused damage to human health and the ecological environment in the process of production, use and disposal, and lead pollution has become o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/622F27B3/08
Inventor 陈海范春华刘伯洋
Owner SHANGHAI MARITIME UNIVERSITY
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