Method for manufacturing bismuth sodium titanate-barium titanate ferro-electricity single crystal

A bismuth sodium titanate, ferroelectric single crystal technology, applied in the direction of single crystal growth, single crystal growth, chemical instruments and methods, etc., can solve the problems of small crystal size, difficulty in practical application, and large number of nucleation

Active Publication Date: 2008-07-16
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method of slow cooling with flux has its inherent disadvantages: the crystallization process is realized by spontaneous nucleation, the number of nuclei is large, and the crystal growth process is difficult to control; the grown crystal size is small, and it is difficult to achieve the purpose of practical use
However, to date, no publication has disclosed a method for the preparation of a relaxed ferroelectric single crystal NBBT grown by the top-seeded flux-pulling method.

Method used

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  • Method for manufacturing bismuth sodium titanate-barium titanate ferro-electricity single crystal
  • Method for manufacturing bismuth sodium titanate-barium titanate ferro-electricity single crystal
  • Method for manufacturing bismuth sodium titanate-barium titanate ferro-electricity single crystal

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Experimental program
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Embodiment 1

[0033] Sodium carbonate, bismuth oxide, titanium dioxide and barium carbonate with a purity of 99.99% are dried according to 0.94Na 0.5 Bi 0.5 TiO 3 -0.06BaTiO 3 The chemical composition ratio was mixed and ball milled for 100 hours, then placed in a covered platinum crucible and heat-treated at 1200°C for 20 hours. Then the resulting product is finely ground and sieved, and a certain proportion of sodium carbonate and bismuth oxide is added as a flux based on the total amount of polycrystalline raw materials, and the molar ratio is Na 2 CO 3 : Bi 2 o3 : 0.94NBT-0.06BT is equal to 5:5:100, and placed in a covered platinum crucible again for heat treatment at 1200°C for 20 hours. Finally, the product is pulverized, finely ground, sieved, and pressed into blocks by cold isostatic pressing. The raw materials pressed into blocks are loaded into a platinum growth crucible, and the growth crucible is placed in the growth furnace shown in FIG. 1 . Raise the temperature to comp...

Embodiment 2

[0035] Sodium carbonate, bismuth oxide, titanium dioxide and barium carbonate with a purity of 99.99% are dried according to 0.90Na 0.5 Bi 0.5 TiO 3 -0.10BaTiO 3 The stoichiometric ratio is weighed, and then additional sodium carbonate and bismuth oxide are weighed as flux, so that Na 2 CO 3 : Bi 2 o 3 : The molar ratio of 0.90NBT-0.10BT is equal to 10:10:100, mixed and ball milled for 100 hours, placed in a covered platinum crucible and heat treated at 1200°C for 20 hours. The resulting product is then finely ground, sieved, and cold isostatically pressed into blocks. The raw materials pressed into blocks are loaded into a platinum growth crucible, and the growth crucible is placed in the growth furnace shown in FIG. 1 . Raise the temperature to completely melt the raw materials, then overheat to 100°C, and keep the temperature for 5 hours, so that the high-temperature solution is fully convected and mixed evenly. Slowly lower the temperature to the solution saturatio...

Embodiment 3

[0037] Sodium carbonate, bismuth oxide, titanium dioxide and barium carbonate with a purity of 99.99% are dried according to 0.85Na 0.5 Bi 0.5 TiO 3 -0.15BaTiO 3 The stoichiometric ratio is weighed, and then additional sodium carbonate and bismuth oxide are weighed as flux, so that Na 2 CO 3 : Bi 2 o 3 : The molar ratio of 0.85NBT-0.15BT is equal to 30:30:100, and the weighed raw materials are put into the platinum growth crucible, and the growth crucible is then placed in the growth furnace shown in FIG. 1 . Raise the temperature to completely melt the raw materials, then overheat to 100°C, and keep the temperature for 5 hours, so that the high-temperature solution is fully convected and mixed evenly. Slowly lower the temperature to the solution saturation point temperature, use platinum wire as the seed crystal, and select the appropriate pulling speed and rotation speed for NBBT crystal growth. During the crystal growth process, the temperature was lowered at a cooli...

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Abstract

A preparing method of bismuth sodium titanate-barium titanate ferroelectric single crystal belongs to the field of crystal growth. The preparing method provided by the invention comprises a series of single crystal growth processes: raw material treatment, heating and melting, growing and cooling. The rotational speed of a seed rod is 10 to 50rpm, and the drawing rate is 0.1mm to 20mm per day, and the cooling rate is 1 to 20 DEG C per day; the cooling rate is 10 to 150 DEG C per hour after the crystal finishes growing. The technology provided by the invention can grow bismuth sodium titanate-barium titanate ferroelectric single crystal (NBBT) with the diameter larger than 40mm and the length larger than 10mm, and the piezoelectric constant d33 can reach 280pC / N, and the electromechanical coupling factor kt can reach 50 percent. The material with the piezoelectric property which reaches the level of leaded piezoelectric materials of PZT ceramics, etc., can be applied in practice.

Description

technical field [0001] The invention relates to a preparation method of sodium bismuth titanate-barium titanate piezoelectric single crystal, belonging to the field of crystal growth. Background technique [0002] At present, piezoelectric materials widely used in the field of piezoelectric transducers, drivers, filters and sensors are all lead-containing materials, such as PZT ceramics, PCM ceramics, and the like. Lead oxide is used as a raw material in the preparation of these lead-based piezoelectric materials, and the amount used accounts for about 70% of the total mass of raw materials. Lead oxide is a highly toxic substance, which is easily volatilized during ceramic sintering, causing environmental pollution and endangering human health; in addition, the cost of lead-containing waste is high and difficult, and it will cause secondary pollution to the environment. In recent years, with people's attention to sustainable development, countries have begun to take measure...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/32C30B15/00
Inventor 葛文伟罗豪甦刘洪赵祥永林迪李晓兵徐海清潘晓明
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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