A thin sheet micro-nano(k,na)nbo 3 Crystal and its preparation method

A micro-nano and thin-sheet technology, applied in the direction of nanotechnology, nanotechnology, chemical instruments and methods, etc., can solve the problems of difficult control of reaction time, KNN purity and thickness, many intermediate phases produced, unfavorable mass production, etc., to achieve excellent chemistry Stability, narrow particle size distribution, effect of increasing surface potential

Active Publication Date: 2020-11-03
TIANJIN CHENGJIAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] When the traditional hydrothermal method is used to prepare synthetic flake KNN, most of them are based on the template method, the preparation process is complicated, and there are many intermediate phases, and the long reaction time also makes it difficult to control the purity and thickness of the final KNN. In addition, the simple hydrothermal synthesis of these compounds also requires a very high alkaline solution (10mol / L) as a mineralizer, which has high production costs and is not conducive to mass production. It is too limited in practical applications, so the traditional The hydrothermal method needs further improvement

Method used

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  • A thin sheet micro-nano(k,na)nbo <sub>3</sub> Crystal and its preparation method
  • A thin sheet micro-nano(k,na)nbo <sub>3</sub> Crystal and its preparation method
  • A thin sheet micro-nano(k,na)nbo <sub>3</sub> Crystal and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Weigh 30ml of ethylene glycol as a solvent, then add 5.88g KOH, 1.8g NaOH, 3g Nb 2 o 5 Stir slowly with a glass rod until the solute is completely dissolved, then put it on a magnetic stirrer and stir for 30 minutes, then pour it into a hydrothermal kettle, heat it in water at 180°C for 8 hours, centrifuge at 8000r / min for 3 minutes, and then use distilled water and no Wash twice with water and ethanol, and dry in an oven at 60°C to obtain flaky micro-nano (K, Na)NbO 3 Crystal powder.

[0026] figure 1 (K, Na)NbO in this example 3 Scanning electron microscope image of the powder, it can be seen that the product (K, Na)NbO 3 It is based on ultra-thin micro-nano (K, Na) NbO with a diameter of 1-2 μm 3 The crystals are the main ones, and the dispersion is good; in addition, there are also nanoparticles scattered around, and some of them are agglomerated.

[0027] figure 2 (K, Na)NbO in this example 3 The XRD pattern of the powder, it can be seen that the ultra-thi...

Embodiment 2

[0029] Weigh 30ml of ethylene glycol as a solvent, then add 5.88g KOH, 1.8g NaOH, 1.5g Nb 2 o 5 Stir slowly with a glass rod until the solute is completely dissolved, then put it on a magnetic stirrer and stir for 30 minutes, then pour it into a hydrothermal kettle, heat it in water at 200°C for 8 hours, centrifuge at 8000r / min for 3 minutes, and then use distilled water and no Wash twice with water and ethanol, and dry in an oven at 60°C to obtain flaky micro-nano (K, Na)NbO 3 Crystal powder.

[0030] image 3 (K, Na)NbO in this example 3 The scanning electron microscope picture of the powder, it can be seen that the obtained product (K, Na) NbO 3 It is mainly flakes with a diameter of 0.8-1.5 μm. In addition, there are nanoparticles scattered around, and some of them are agglomerated. Compared with Example 1, the flakes obtained under this condition have a smaller particle size .

Embodiment 3

[0032] Weigh 30ml of ethylene glycol as a solvent, then add 5.88g KOH, 1.8g NaOH, 1.5g Nb 2 o 5 , 0.5wt% surfactant PEG, slowly stirred with a glass rod until the solute was completely dissolved, then placed it on a magnetic stirrer and stirred for 30min, then poured it into a hydrothermal kettle, and heated it at 200°C for 8h, 8000r / min centrifuged for 3min, then washed twice with distilled water and absolute ethanol, and dried in an oven at 60°C to obtain ultra-thin flaky micro-nano (K, Na)NbO 3 Crystal powder.

[0033] Figure 4 (K, Na)NbO in this example 3 The scanning electron microscope picture of the powder, it can be seen that the obtained product (K, Na) NbO 3 It is quite different from Example 1 and Example 2, but it is basically composed of flakes, with a particle size of about 1 μm and a slight thickness. In addition, there are products with a honeycomb shape composed of agglomerated nanoparticles Adheres to flakes.

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Abstract

The invention discloses a preparation method of flake micro-nano (K, Na) NbO3 crystals. The preparation method comprises: (1) orderly adding a certain amount of KOH, NaOH, Nb2O5 and a surfactant intoa certain amount of ethylene glycol as a solvent and slowly stirring the solution through a glass rod until the solute is completely dissolved, (2) stirring the mixed solution through a magnetic stirrer for a certain period of time, pouring the solution into a hydrothermal kettle, carrying out hydrothermal treatment for some time, carrying out centrifugation and washing, immersing the mixture in dilute hydrochloric acid and carrying out drying to obtain flake micro-nano (K, Na) NbO3 crystal powder. The preparation method uses ethylene glycol as a solvent, reduces the concentration of a mineralizer required by the traditional hydrothermal method, and improves the stability of the system. By change of different conditions, the obtained product mainly comprises the flake micro-nano (K, Na) NbO3 crystal powder. The flake micro-nano (K, Na) NbO3 crystal has the diameters of 0.2 to 2 micrometers and belongs to the order of micrometers.

Description

technical field [0001] The invention relates to the technical field of chemical material preparation, in particular to a thin-sheet micro-nano (K, Na)NbO 3 Crystals and methods for their preparation. Background technique [0002] In recent years, in order to solve the environmental problems caused by lead-based piezoelectric ceramics containing more than 60% lead, more and more researchers have focused on green materials. Lead-free piezoelectric ceramics have become a hot spot in the field of green materials due to their excellent performance, (K, Na)NbO 3 (KNN) is a typical perovskite-type ferroelectric with high Curie temperature, excellent piezoelectric performance and suitable bandgap band, which is one of the most promising environmentally friendly candidates in this class of ceramics. In addition, the development of green synthesis methods also occupies an important position, applying the principles of green and sustainable chemistry, reducing the use of dangerous, e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G33/00B82Y40/00B82Y30/00
CPCB82Y30/00B82Y40/00C01G33/006C01P2002/34C01P2002/72C01P2004/03C01P2004/61C01P2004/62
Inventor 赵巍张琪荣嘉诚王虎刚李明晓
Owner TIANJIN CHENGJIAN UNIV
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