Method for growing relaxor ferroelectric single crystal by top seed crystal method

A relaxor ferroelectric single crystal and crystal growth technology, applied in the direction of single crystal growth, single crystal growth, crystal growth, etc., can solve the problems of complex crystallization route, difficult crystal growth, etc., to achieve simple process, reliability and practicability The effect of strong and lower production cost

Inactive Publication Date: 2022-07-15
DONGGUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] In recent years, due to its excellent piezoelectric, dielectric and acoustic impedance properties, relaxor ferroelectric single crystals have been widely used in the preparation of medical broadband high-frequency high-sensitivity ultrasonic transducers, marine resource broadband ultrasonic detection, and ultrasonic drivers. Especially in the preparation of underwater acoustic transducers for sonar systems, the main technical bottleneck in the commercial application of relaxor ferroelectric single crystals lies in the preparation of single crystals. Since relaxor ferroelectric single crystals are formed in a multi-component system, for example PbO-MgO(ZnO)-Nb 2 o 5 -TiO 2 system, so complex crystallization routes will appear during the cooling of the melt, making crystal growth difficult

Method used

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  • Method for growing relaxor ferroelectric single crystal by top seed crystal method
  • Method for growing relaxor ferroelectric single crystal by top seed crystal method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] The PZN-PT large-size relaxed ferroelectric single crystal was grown by the top seed method, and the crystal chemical formula was 0.6Pb(Zn 1 / 3 Nb 2 / 3 )O 3 -0.4PbTiO 3 , the single crystal growth method comprises the following steps:

[0054] (1) Preparation of seed crystals

[0055] S21. Weigh PbO, ZnO, Nb according to the stoichiometric ratio of the chemical formula of the relaxation ferroelectric single crystal 2 O 5 , TiO 2 , prepare flux, mix described raw material and flux, grind, load into described crucible;

[0056] S22. Fix the platinum wire on one end of the seed rod, and adjust the center to ensure that the centers of the lava furnace, the crucible and the platinum wire are in a straight line;

[0057] S23. Heat the raw material to 900-1150°C to melt, keep the temperature constant for 1-6d to obtain a melt, then adjust the platinum wire to be in contact with the liquid level of the melt, and cool down at a rate of 2-10°C / d for crystal growth, Rotate...

Embodiment 2

[0067] The difference between Example 2 and Example 1 is that in the preparation step S3 of the PZN-PT large-size relaxed ferroelectric single crystal, the melting temperature of the raw material is controlled at 850-1000°C, and the constant temperature time is 2-3d ; The crystal growth temperature is controlled at 900-1000° C., the cooling rate is 2-8° C. / d, and others are the same as in Example 1.

Embodiment 3

[0069] The difference between Example 3 and Example 1 is that in the preparation step S3 of the PZN-PT large-size relaxed ferroelectric single crystal, the melting temperature of the raw material is controlled at 1100-1150°C, and the constant temperature time is 2-3d ; The crystal growth temperature is controlled at 900-1000° C., the cooling rate is 2-8° C. / d, and others are the same as in Example 1.

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Abstract

The invention relates to a method for growing a relaxor ferroelectric single crystal by a top seed crystal method, a gradient molten salt crystal growth furnace is adopted to grow the single crystal, a seed rod and a crucible in the growth furnace have rotation adjustability, and the method comprises the following steps: S1, weighing raw materials according to the stoichiometric ratio of the chemical formula of the single crystal, preparing a fluxing agent, mixing the raw materials with the fluxing agent, and stirring to obtain a mixed solution; filling the mixture into a crucible; s2, fixing the seed crystal on a seed crystal rod, and ensuring that the molten salt furnace, the crucible and the center of the seed crystal are on the same line; s3, heating the raw materials to a molten state, keeping the temperature constant for a certain time to obtain a melt, then adjusting the seed crystal to be connected with the liquid level of the melt, finding out the temperature of a saturation point, properly cooling at the supersaturation temperature for crystal growth, adjusting the cooling rate according to the crystal growth speed, and rotating a seed crystal rod and a crucible in the growth process to adjust the convection change of the melt; and S4, when the crystal grows to the required size, lifting the crystal from the melt, cooling and annealing to obtain the large-size relaxor ferroelectric single crystal.

Description

technical field [0001] The invention belongs to the technical field of crystal material preparation, and in particular relates to a method for growing a relaxor ferroelectric single crystal by a top seed method. Background technique [0002] In recent years, relaxor ferroelectric single crystals have been widely used in the preparation of medical broadband high-frequency high-sensitivity ultrasonic transducers, marine resources broadband ultrasonic detection, and ultrasonic drivers due to their excellent piezoelectric, dielectric and acoustic impedance properties. Especially in the preparation of underwater acoustic transducers in sonar systems, the main technical bottleneck for the commercial application of relaxor ferroelectric single crystals lies in the preparation of single crystals, because relaxor ferroelectric single crystals are formed in a multi-component system, such as PbO-MgO(ZnO)-Nb 2 O 5 -TiO 2 Therefore, a complex crystallization route will appear during t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B9/12C30B29/22
CPCC30B9/12C30B29/22
Inventor 卢远豪李涛廖文勇何兴晨
Owner DONGGUAN UNIV OF TECH
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