Doping type tantalic acid gallium-lanthanum crystal for high-temperature piezoelectric devices and preparation method thereof

A gallium lanthanum tantalate, doped technology, which is used in the field of doped gallium lanthanum tantalate crystals and its preparation for high-temperature piezoelectric devices, can solve the problems of rarely reported devices, and achieve large-scale, high electromechanical Coupling factor, high-quality effects

Active Publication Date: 2013-06-26
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

Researchers in Japan's Uda laboratory have been working on improving the high-temperature resistivity of LGT crystals. They have studied the effects of growth atmosphere and iridium pollution on the resistivity of LGT. conducted research, and preliminarily proposed the conduction mechanism of the high-temperature resistivity of LGT crystals, but there are few reports on the devices developed using this crystal.
Also from Japan, Hiroaki Takeda and others mainly studied the method of increasing the high-temperature resistivity of LGT crystals by doping Al elements, and achieved some remarkable results. However, the pressure sensor developed using this crystal after optimization is generally used at about 500°C.

Method used

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  • Doping type tantalic acid gallium-lanthanum crystal for high-temperature piezoelectric devices and preparation method thereof
  • Doping type tantalic acid gallium-lanthanum crystal for high-temperature piezoelectric devices and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Preparation of 0.5% Ba:La 3 Ta 0.5 Ga 5.5 o 14

[0041] (1) use La 2 o 3 , Ga 2 o 3 、 Ta 2 o 5 and BaCO 3 As the initial raw material, roasted and dried

[0042] Press 0.5%Ba:La first 3 Ta 0.5 Ga 5.5 o 14 The molar ratio of chemical formula La 2 o 3 : Ga 2 o 3 : Ta 2 o 5 : BaCO 3 =1.5:2.75:0.25:0.0015 Weigh the raw material and add more Ga 2 o 3 Mass 1% Ga 2 o 3 , so that Ga 2 o 3 Excess 1%, mixed, compacted, put into alumina crucible and sintered at 1200°C for 24 hours to obtain Ba-LGT polycrystalline material.

[0043] (2) Place the Ba-LGT polycrystalline material in a platinum or iridium crucible. Single crystal furnace is evacuated and filled with protective gas: N 2 +(1~2vol%O 2 ), using intermediate frequency heating, heating up to melt the raw material and keeping it warm for 2 to 10 hours, and then cooling down to near the melting point; inserting the seed crystal, using the LGT seed crystal in the z direction, necking and shoulderi...

Embodiment 2

[0047] Preparation of 0.1% Mo:La 3 Ta 0.5 Ga 5.5 o 14

[0048] (1) use La 2 o 3 , Ga 2 o 3 、 Ta 2 o 5 and MoO 3 As the initial raw material, roasted and dried

[0049] Press 0.1%Mo:La first 3 Ta 0.5 Ga 5.5 o 14 The molar ratio of chemical formula La 2 o 3 : Ga 2 o 3 : Ta 2 o 5 : MoO 3 =1.5:2.75:0.25:0.003 Weigh the raw material and add more Ga 2 o 3 2% Ga by mass 2 o 3 , so that Ga 2 o 3 2% in excess, mixed evenly, compacted, put into an alumina crucible and sintered at 1200° C. for 20 hours to obtain Mo-LGT polycrystalline material.

[0050] (2) Place the Mo-LGT polycrystalline material in a platinum or iridium crucible. Vacuumize the single crystal furnace, fill it with 100% Ar gas, use intermediate frequency heating, heat up to melt the raw material and keep it warm for 2 to 10 hours, and then cool down to near the melting point; put in the seed crystal, use the LGT seed crystal in the x direction, and Put the shoulders behind the neck and grow ...

Embodiment 3

[0054] Preparation of 1% Al:La 3 Ta 0.5 Ga 5 o 14 (i.e. La 3 Ta 0.5 Ga 5 al 0.5 o 14 )

[0055] (1) use La 2 o 3 , Ga 2 o 3 、 Ta 2 o 5 and Al 2 o 3 As the initial raw material, roasted and dried

[0056] Press 1%Al:La first 3 Ta 0.5 Ga 5 o 14 The molar ratio of chemical formula La 2 o 3 : Ga 2 o 3 : Ta 2 o 5 :Al 2 o 3 = 1: 1.667: 0.167: 0.136 Weigh the raw material and add more Ga 2 o 3 2% Ga by mass 2 o 3 , so that Ga 2 o 3 Excessive 2%, mixed, compacted, put into alumina crucible and sintered at 1250°C for 18 hours to obtain Al-LGT polycrystalline material.

[0057] (2) Place the Al-LGT polycrystalline material in a platinum or iridium crucible. The single crystal furnace is evacuated and filled with protective gas: Ar+1~2%O 2 (volume percentage), using intermediate frequency heating, heat up to melt the raw material and keep it warm for 2 to 10 hours, and then cool down to near the melting point; put in the seed crystal, use the LGT seed ...

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Abstract

The invention relates to a doping type tantalic acid gallium-lanthanum crystal for high-temperature piezoelectric devices and a preparation method of the doping type tantalic acid gallium-lanthanum crystal. The general formula of the doping type tantalic acid gallium-lanthanum (M-LGT) crystal is y%M: La3Ta0.5+xGa5.5-xO14, wherein x is larger than or equal to -0.3 and smaller than or equal to 0.3, y is larger than or equal to 3.0 and smaller than or equal to 2, and a doping element M is at least selected from one of Ba, Mo and Al. The crystal can be prepared through adopting crystal growing methods such as a czochralski method and a bridgeman-stockbarger method, and the electrical resistivity of the crystal at high temperature can be obviously increased through optimizing growing atmosphere, doping elements and post treating. A piezoelectric element which is produced by the crystal is firstly and successfully applied to a high-temperature piezoelectricity acceleration sensor of -200 DEG C-649DEG C, and the doping type high-electrical resistivity LGT crystal material has a bright application prospect in future piezoelectric devices.

Description

technical field [0001] The present invention relates to a doped type, high resistivity gallium lanthanum tantalate (LGT) piezoelectric crystal material which can be used in high-temperature and low-temperature piezoelectric devices, its preparation method and its application in high-temperature piezoelectric devices, especially sensors, resonators or application of filters. Background technique [0002] Piezoelectric crystal materials are widely used in ultrasonic transducers, SAW devices, piezoelectric oscillators, piezoelectric filters, sensors and other fields. The piezoelectric crystals that have been commercialized at present are mainly single crystal quartz (α-SiO 2 ) and lithium niobate (LiNbO 3 ), the most attractive feature of quartz is the cut type with zero-frequency temperature coefficient, and its temperature stability is very good, but its piezoelectric constant and electromechanical coupling coefficient are low; at the same time, quartz is stable under press...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/30C30B15/00C30B11/00C30B33/02
Inventor 高攀涂小牛孔海宽忻隽郑燕青施尔畏
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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