Microwave molten salt process for synthesizing plate Sr3Ti2O7 crystal

A flake crystal and flux technology, applied in the field of artificial crystal growth, can solve the problems of high energy consumption and shortening crystallization time, etc.

Inactive Publication Date: 2007-03-21
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Synthesis of Sr by Conventional Molten Salt Method 3 Ti 2 o 7 Flaky crystals need to be processed at a high temperature of 1200 ° C to 1300 ° C, which requires high energy consumption. Therefore, how to improve the process and reduce Sr 3 Ti 2 o 7 The synthesis temperature and shortening the crystallization time have become important research topics

Method used

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  • Microwave molten salt process for synthesizing plate Sr3Ti2O7 crystal
  • Microwave molten salt process for synthesizing plate Sr3Ti2O7 crystal

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] SrCO with a purity greater than 99% 3 And TiO with a purity greater than 99% 2 Is the starting reactant, press SrCO 3 : TiO 2 =3:2 stoichiometric ratio for batching; mix and ball mill the prepared starting reaction materials for 6 hours, and then add flux NaCl and KCl. The ratio of the mass of flux to the total mass of the starting reactant is 0.5:1, NaCl The molar ratio of KCl to KCl is 1:1, and then the ball mill is mixed for 6 hours; the dispersant of the two mixed ball mills is anhydrous ethanol; the material after the ball milling is dried in the air at 70℃, and the dried material is After pressing the tablet, put it into the corundum crucible and heat it in a microwave vacuum sintering furnace at 700℃ for 2 hours. The material after the heat treatment is washed repeatedly with deionized water until the water is washed out with AgNO 3 If no chloride ion is detected, perovskite Sr is obtained 3 Ti 2 O 7 Flake crystals.

Embodiment 2

[0020] SrCO with a purity greater than 99% 3 And TiO with a purity greater than 99% 2 Is the starting reactant, press SrCO 3 : TiO 2 =3:2 stoichiometric ratio for batching; mix and ball mill the prepared starting reaction materials for 12 hours, and then add flux NaCl and KCl. The ratio of the mass of flux to the total mass of the starting reactant is 0.5:1, NaCl The molar ratio of KCl and KCl is 1:1, and then the ball mill is mixed for 12 hours; the dispersant of the two mixed ball mills is anhydrous ethanol; the material after the ball milling is dried in the air at 70°C, and the dried material is After pressing the tablet, put it into the corundum crucible and heat it in a microwave vacuum sintering furnace at 700℃ for 2 hours. The material after the heat treatment is washed repeatedly with deionized water until the water is washed with AgNO 3 If no chloride ion is detected, perovskite Sr is obtained 3 Ti 2 O 7 Flake crystals.

Embodiment 3

[0022] SrCO with a purity greater than 99% 3 And TiO with a purity greater than 99% 2 Is the starting reactant, press SrCO 3 : TiO 2 =3:2 stoichiometric ratio for batching; mix and ball mill the prepared starting reaction materials for 6 hours, and then add flux NaCl and KCl. The ratio of the mass of the flux to the total mass of the starting reactant is 1:1, NaCl The molar ratio of KCl and KCl is 1:1, and then the ball mill is mixed for 12 hours; the dispersant of the two mixed ball mills is anhydrous ethanol; the material after the ball milling is dried in the air at 70°C, and the dried material is After pressing the tablet, put it into the corundum crucible and heat it in a microwave vacuum sintering furnace at 700℃ for 2 hours. The material after the heat treatment is washed repeatedly with deionized water until the water is washed with AgNO 3 If no chloride ion is detected, perovskite Sr is obtained 3 Ti 2 O 7 Flake crystals.

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Abstract

The present invention discloses microwave molten salt process for synthesizing plate Sr3Ti2O7 crystal, and microwave field is introduced into molten salt process to synthesize plate Sr3Ti2O7 crystal at low temperature. The process with SrTiO3 and TiO2 as materials includes homogeneous mixing with flux NaCl-KCl and maintaining in microwave at 700-750 deg.c for 1-6 hr. XRD and SEM analysis on the product structure shows that during the microwave molten salt process, obvious plate Sr3Ti2O7 crystal of 5 micron size is obtained after maintaining at 700 deg.c for 30 min and plate Sr3Ti2O7 crystal of 10 micron size is obtained after maintaining at 750 deg.c for 3 hr. Compared with conventional molten salt process, the microwave molten salt process has lowered Sr3Ti2O7 crystal synthesizing temperature, shortened crystallization time and greatly lowered power consumption.

Description

Technical field [0001] The invention relates to an artificial crystal growth method, in particular to a method for synthesizing flake crystal Sr in a molten salt method. 3 Ti 2 O 7 Introducing a microwave field into the method to enable crystals to grow at low temperatures. Background technique [0002] SrTiO 3 It is a typical perovskite-type multifunctional ceramic, which has the advantages of superconductivity, semiconductivity, gas sensitivity, heat sensitivity, photosensitivity, high dielectric constant and low dielectric loss, so it is widely used in the electronics industry An electronic ceramic material. SrTiO with flaky crystal structure 3 The preparation of SrTiO is the object of attention, mainly because it exhibits the following characteristics: (1) For a given area, flake or layered SrTiO 3 The crystal can yield into a thinner film, which can improve the performance of the thinner ceramic powder required by the multilayer capacitor; (2) Using SrTiO 3 The flake crystal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/47C04B35/622
Inventor 刘韩星徐林曹明贺
Owner WUHAN UNIV OF TECH
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