Growing method of (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal

A potassium-sodium niobate-based, lead-free piezoelectric technology, applied in the direction of single crystal growth, single crystal growth, crystal growth, etc., can solve the problem of harsh operating conditions and equipment requirements, affecting the integrity of crystal components, and the raw material potassium and sodium are volatile and other issues to achieve the effect of low requirements, improved integrity, and short cycle

Inactive Publication Date: 2014-11-19
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention aims at the high temperature in the growth process of potassium sodium niobate base (KNN) lead-free piezoelectric single crystal in the prior art, which requires harsh operating conditions and equipment, consumes time and energy, and the raw material potassium and sodium are easy to volatilize, thus affecting the crystal. The technical problem of the integrity of the composition is to provide a new method for growing potassium sodium niobate-based lead-free piezoelectric single crystal at low temperature. The method of the present invention can realize the preparation of KNN-based lead-free lead piezoelectric single crystal

Method used

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  • Growing method of (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal
  • Growing method of (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal
  • Growing method of (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal

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Experimental program
Comparison scheme
Effect test

Embodiment 1～8

[0032] Embodiment 1~8 crucible descending method growth (K x Na 1-x ) 1-y Li y NbO 3 single crystal

[0033] 1. Will K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 Dry at 300°C for 3 hours, then press the chemical formula (K x Na 1-x ) 1-y Li y NbO 3 The stoichiometric ratio weighs K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 and Nb 2 o 5 raw powder.

[0034] 2. Weigh the flux, and mix well to obtain the starting material for crystal growth.

[0035] 3. Put the starting material into the platinum crucible, put the crucible in the alumina ceramic downcomer, and then place it in the crucible drop method crystal growth furnace.

[0036] 4. The crucible is kept at T1 for t1 hours, and then the temperature is raised to T2 for t2 hours, so that all the starting materials are melted, and then the crucible descends at the speed of v1, and when passing through the temperature gradient field between the high temperature zone and the low temperature zone in the growth furnace , the melt gra...

Embodiment 1

[0042] The potassium sodium niobate-based lead-free piezoelectric single crystal obtained in Example 1 was ground into powder, and its structure was analyzed by X-ray diffraction. figure 1 It can be seen that the structure of potassium sodium niobate-based lead-free piezoelectric single crystal is a pure perovskite structure, and no other impurity phases are formed.

[0043] Then test the obtained potassium-sodium niobate-based lead-free piezoelectric single crystal at different frequencies, the dielectric constant versus temperature curve, the dielectric temperature curve is as follows figure 2 shown, from figure 2 It can be seen that there are two dielectric anomaly peaks at all frequencies, corresponding to the orthorhombic-tetragonal phase transition (192 °C) and the tetragonal-cubic phase transition (Curie temperature T c : 426°C). Finally, the piezoelectric performance of the obtained crystal is tested, and the piezoelectric constant can reach 410pC / N. The obtained c...

Embodiment 9～15

[0044] Growth (K x Na 1-x ) 1-y Li y NbO 3 single crystal

[0045] 1. Will K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 Dry at 300°C for 3 hours, then press the chemical formula (K x Na 1-x ) 1-y Li y NbO 3 The stoichiometric ratio weighs K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 and Nb 2 o 5 raw powder.

[0046] 2. Weigh the fluxing agent, mix well and evenly to obtain the starting material for crystal growth.

[0047] 3. Put the starting material into the platinum crucible and seal it. Put the sealed platinum crucible into the glass tube. The glass tube is vacuum-sealed and then placed in the muffle furnace.

[0048] 4. The temperature in the muffle furnace rises from room temperature to T1 after t10 hours and keeps warm for t1 hours, then rises to T2 after t20 hours and keeps warm for t2 hours, then the temperature in the muffle furnace cools to room temperature at v2 speed.

[0049] 5. After the crystal growth is completed, the crystal is released from the furnace, the c...

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Abstract

The invention discloses a method for growing a (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal. The method comprises the following steps: weighing raw material powder; weighing a fluxing agent and mixing with the raw material powder; putting the starting material into a crucible and putting the crucible into a furnace; carrying out heat preservation on the crucible at a temperature of 400 DEG C to 900 DEG C for 2 to 20 hours, then heating to 700 DEG C to 1000 DEG C, carrying out heat preservation for 2 to 20 hours until the starting material is completely molten and cooling the interior of the furnace to a room temperature at the speed of 1 to 200 DEG C/h so as to obtain the (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal. The (KxNa1-x)1-yLiyNbO3-based lead-free piezoelectric monocrystal grown by virtue of a low-temperature preparation technology is of a pure perovskite structure and cannot generate impure phases. The method has the advantages that 1, the crystal grows at a low temperature and has a short growth period; 2, the requirement on a growing instrument is low during a low-temperature growing process; 3, the raw material powder contained in the crucible can be conveniently sealed and is nearly not volatilized due to a low growing temperature, so that the components of the growing crystal can be well controlled so as to prevent the deviation of the components.

Description

technical field [0001] The invention belongs to the field of piezoelectric crystal materials, and in particular relates to a method for growing a potassium-sodium niobate-based lead-free piezoelectric single crystal. Background technique [0002] Piezoelectric materials are a very important class of functional materials, which can realize the conversion between mechanical energy and electrical energy through the direct piezoelectric effect and the inverse piezoelectric effect. Piezoelectric materials are widely used in electronics, communications, aerospace, medical, military and other fields due to their special physical properties such as piezoelectricity, ferroelectricity, dielectricity, pyroelectricity and optoelectronics. With rapid development, its scope of application will continue to expand. But so far, the dominant piezoelectric materials are all lead-containing materials, such as lead zirconate titanate (PZT), etc. At present, such materials are still used to prep...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B11/00C30B29/30
Inventor 刘莹许桂生刘锦峰杨丹凤
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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