KR101650656B1 - Method of manufacturing a platelet perovskite structure - Google Patents
Method of manufacturing a platelet perovskite structure Download PDFInfo
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- KR101650656B1 KR101650656B1 KR1020150080523A KR20150080523A KR101650656B1 KR 101650656 B1 KR101650656 B1 KR 101650656B1 KR 1020150080523 A KR1020150080523 A KR 1020150080523A KR 20150080523 A KR20150080523 A KR 20150080523A KR 101650656 B1 KR101650656 B1 KR 101650656B1
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- C01G23/00—Compounds of titanium
- C01G23/04—Oxides; Hydroxides
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G33/00—Compounds of niobium
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- C—CHEMISTRY; METALLURGY
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- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2002/00—Crystal-structural characteristics
- C01P2002/30—Three-dimensional structures
- C01P2002/34—Three-dimensional structures perovskite-type (ABO3)
Abstract
Description
The present invention relates to a method for producing a sheet-like perovskite structure, and more particularly, to a method for manufacturing a sheet-like material or a piezoelectric nano-generator in a template grain growth (TGG) Thereby producing a sheet-like perovskite structure.
The flaked perovskite structure can be used as a seed material in the template grain growth process. Here, examples of the plate-like perovskite structure may be a material consisting of BaTiO 3, SrTiO 3, or KNbO 3.
The textured ceramics formed through the template grain growth (TGG) process using the sheet-like perovskite structure as a seed material have high piezoelectric properties and dielectric properties similar to single crystal materials.
On the other hand, a perovskite structure can be mixed with a polymer and used for synthesizing a piezoelectric nano-generator. This allows the sheet-like perovskite structure to be effectively aligned within the polymer to produce good output electrical energy.
However, since the plate-shaped perovskite structure has a very large symmetry, a plate-shaped perovskite structure having a high aspect ratio in the conventional ceramic synthesis process such as a flux process and a hydrothermal synthesis process is manufactured There is a difficulty in doing.
Accordingly, a process of converting a precursor having a morphology such as a plate into a plate-like perovskite is used as in a topochemical microcrystal conversion (TMC) process. However, the TMC process is very complicated and takes a long time.
It is an object of the present invention to provide a method for producing a sheet-like perovskite structure having a (Na 1-x K x ) NbO 3 structure through simplified processes.
In order to achieve the above object, the present invention provides a method for producing a plate-shaped perovskite structure having a (Na 1-x K x ) NbO 3 structure, comprising the steps of: (1-y) NaOH-yKOH (K 8-8 x Na 8x ) Nb 6 O 19 .nH 2 O precursor (where 0 <x <1) is formed by hydrothermal synthesis using Nb 2 O 5 as the starting material . Thereafter, an annealing process is performed on the precursor.
In one embodiment of the present invention, the hydrothermal synthesis process may be performed at a temperature ranging from 120 to 160 ° C.
In one embodiment of the present invention, the annealing process may be performed in a temperature range of 450 to 600 ° C for 6-12 hours.
In one embodiment of the present invention, a process may be further performed to remove water from the precursor through the vaporization process for the precursor before the annealing process. Here, the vaporization process may be performed at a temperature ranging from 120 to 170 ° C.
In accordance with embodiments of the present invention, a hydrothermal synthesis process (K 8-8 x Na 8x ) is performed using (1-y) NaOH-yKOH (where 0.35 ≦ y ≦ 0.90) and Nb 2 O 5 as starting materials, Forming a Nb 6 O 19 .nH 2 O precursor (where 0 <x <1) and annealing the precursor to form a plate-like perovskite structure having a (Na 1-x K x ) NbO 3 structure Can be produced. Therefore, unlike the conventional topochemical microcrystal conversion (TMC) process, a plate-like perovskite structure having a (Na 1-x K x ) NbO 3 structure can be easily produced through a simple process .
1 is a graph showing an XRD pattern for a KNNH precursor formed according to Synthesis Example 1. FIG.
FIG. 2 is a graph showing an XRD pattern for a KNN platy perovskite structure manufactured according to Example 1. FIG.
3 is a scanning electron micrograph of a KNNH precursor formed according to Synthesis Example 1. Fig.
4 is a scanning electron micrograph of a KNN platy perovskite structure formed according to Example 1. FIG.
5 is an EDX analysis graph for a KNN platy perovskite structure formed according to Example 1. FIG.
6 is a scanning electron micrograph of a KNN platy perovskite structure formed according to Examples 1 and 2 and Comparative Examples 1 and 2.
7A is a transmission electron micrograph of a KNN platy perovskite structure formed according to Example 1. FIG.
7B is a photograph showing an electron scattering pattern for a KNN platy perovskite structure formed according to Example 1. FIG.
7C is a high-performance transmission electron micrograph of a KNN platy perovskite structure formed according to Example 1. FIG.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In the accompanying drawings, the sizes and the quantities of objects are shown enlarged or reduced from the actual size for the sake of clarity of the present invention.
The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.
The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprise", "comprising", and the like are intended to specify that there is a feature, step, function, element, or combination of features disclosed in the specification, Quot; or " an " or < / RTI > combinations thereof.
On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.
(Na 1-x K x ) NbO 3 Method for manufacturing a sheet-like perovskite structure having a structural formula
First, Nb 6 O 19 .nH (K 8-8x Na 8x ) was prepared by hydrothermal synthesis using (1-y) NaOH-yKOH (where 0.35 ≦ y ≦ 0.90) and Nb 2 O 5 2 O precursor (where 0 < x < 1). The (K 8-8x Na 8x ) Nb 6 O 19 .nH 2 O precursor may have a plate-like structure. The (K 8-8x Na 8x ) Nb 6 O 19 .nH 2 O precursor may have a relatively low surface roughness and a relatively high aspect ratio.
In the hydrothermal synthesis step, distilled water may be used as the solvent in the temperature range of 120 to 160 ° C.
Subsequently, an annealing process is performed on the precursor to produce a sheet-like perovskite structure having a (Na 1-x K x ) NbO 3 structure.
The annealing process may be performed for 6-12 hours at a temperature range of 450 to 700 ° C. The platy perovskite structure may have a rough surface.
In one embodiment of the present invention, a process may be further performed to remove water from the precursor through the vaporization process for the precursor before the annealing process. Here, the vaporization process may be performed at a temperature ranging from 120 to 150 ° C. Thereby, water is removed from the precursor through the vaporization process before the annealing process. Therefore, the phenomenon that the surface roughness of the platy perovskite structure is increased by vaporization of water from the precursor in the subsequent annealing process can be suppressed.
Example
Synthesis Example 1: Synthesis of KNNH precursor
Potassium hydroxide (KOH) and sodium hydroxide (NaOH) and niobium oxide (Nb 2 O 5 ) were used as starting materials. A solution of 14 mol of (1-y) NaOH-yKOH (y = 0.35, 0.5, 0.8 or 0.9) was diluted in distilled water (40 ml) and 0.002 mol of niobium oxide (Nb 2 O 5 ) was added to form a mixture. The mixture was then poured into a container for 2 hours. The mixture was then heated in a sterilizer autoclave for about 8 hours at a temperature of 160 ° C. Thereafter, a (K 8-8 x Na 8x ) Nb 6 O 19 .nH 2 O precursor (where 0 <x <1) (KNNH precursor) was formed through a filtering process and a cleaning / drying process.
Example 1: Preparation of a KNN flaked perovskite structure
The KNNH precursor formed in Synthesis Example 1 was annealed at 600 ° C for about 6 hours to prepare a KNN platy perovskite structure.
Example 2: Preparation of a KNN platy perovskite structure
The KNNH precursor formed in Synthesis Example 1 was subjected to a vaporization process at 120 ° C for about 12 hours to remove water from the KNNH precursor. Then, the water-removed precursor was subjected to an annealing process at a temperature of 600 ° C for about 6 hours to prepare a KNN platy perovskite structure.
Comparative Example 1: Preparation of a KNN plate-shaped perovskite structure
The KNNH precursor formed in Synthesis Example 1 was subjected to an annealing process at 700 ° C for about 6 hours to prepare a KNN platy perovskite structure.
Comparative Example 2: Preparation of KNN plate-shaped perovskite structure
The KNNH precursor formed in Synthesis Example 1 was annealed at 500 ° C for about 12 hours to prepare a KNN platy perovskite structure.
Evaluation of KNN plateau perovskite structure
XRD (X-ray Diffraction) apparatus was used to confirm the structural characteristics of the specimens prepared according to Synthesis Example 1 and Examples 1 and 2. An EDX (energy-dispersive X-ray spectroscope) apparatus was used for the composition of the NKN platy perovskite structure prepared according to Examples 1 and 2. Synthesis Example 1 and Example Scanning Electron Spectroscope equipment was used to confirm the morphology of the specimens prepared according to Examples 1 and 2. The NKN platy perovskite structure prepared according to Examples 1 and 2 Field-emission transmission electron microscopy (FE-TEM) was used to identify growth directions.
1 is a graph showing an XRD pattern for a KNNH precursor formed according to Synthesis Example 1. FIG. (A) y = 0.0, (b) y = 0.35, (c) y = 0.50, (d) y = 0.90 and (a) y = 1.0.
Referring to FIG. 1, a synthesis product synthesized according to the y value through a hydrothermal synthesis process using (1-y) NaOH-yKOH (where 0? Y? 1) and Nb 2 O 5 as starting materials, XRD pattern. The hydrothermal synthesis process was carried out at a temperature of 160 ° C for 8 hours.
In this case, (a), NaNbO 3 (NN), Na 2 Nb 2 O 6 H 2 O (SOMS) and Na 8 Nb 6 O 19 .13H 2 O phases were confirmed, respectively. The Na 2 Nb 2 O 6 H 2 O (SOMS) and Na 8 Nb 6 O 19 .13H 2 O phases are transitional phases, which are heat treated at high temperature and converted to NaNbO 3 (NN) phase.
Particularly, in the range (b to e) of 0.35? Y? 0.90 , a low temperature plate (K 8-8x Na 8x ) Nb 6 O 19 .nH 2 O (where 0 <x <1, KNNH) precursor is formed , Can be converted to (Na 1-x K x ) NbO 3 phase in the temperature range of about 450-700 ° C.
On the other hand, when y = 1 (f), KNbO 3 (KN) phase is formed when only KOH except NaOH is used.
FIG. 2 is a graph showing an XRD pattern for a KNN platy perovskite structure manufactured according to Example 1. FIG. (A) y = 0.0, (b) y = 0.35, (c) y = 0.50, (d) y = 0.90 and (a) y = 1.0.
Referring to Figure 2, K 8-8x Na 8x formed in Synthesis Example 1) Nb 6 O 19 · nH 2 O precursor (where, 0 <x <1 The number of, KNNH) The annealing process is performed for the plate-like KNN Fe A robust structure was prepared. At this time, the annealing process was performed at a temperature of 500 ° C for 6 hours.
Referring to FIG. 2, when y = 0, the Na 2 Nb 2 O 6 H 2 O (SOMS) and Na 8 Nb 6 O 19 · 13H 2 O phases are reacted with NaNbO 3 (NN ). On the other hand, in the range of 0.35? Y? 0.90 (b to e), KNNH phases occupy the majority. It can be confirmed that the KNNH phase is converted into (Na 1-x K x ) NbO 3 (NKN) phase. Further, when y = 1 (f), it can be confirmed that a KNbO 3 (KN) phase is formed.
3 is a scanning electron micrograph of a KNNH precursor formed according to Synthesis Example 1. Fig. Here, (a) y = 0.35, (b) y = 0.50, (c) y = 0.80 and (d) y = 0.90.
3, the (K 8-8x Na 8x ) Nb 6 O 19 .nH 2 O (KNNH) precursor (where 0 <x <1) particles formed according to Synthesis Example 1 all have a smooth surface It can be confirmed that it has a plate shape. In particular, in the case of y? 0.5, the KNNH precursor may have a thickness of 0.2 to 0.3 μm and a length of about 1.5 μm (see (a) and (b)). On the other hand, in the case of 0.8? Y? 0.9, the KNNH precursor may have a thickness of about 0.1 to 0.25 mu m and a length of about 2.5 mu m (see (c) and (d)
4 is a scanning electron micrograph of a KNN platy perovskite structure formed according to Example 1. FIG. Here, (a) y = 0.35, (b) y = 0.50, (c) y = 0.80 and (d) y = 0.90.
4, an annealing process is performed on the K 8-8x Na 8x ) Nb 6 O 19 .nH 2 O precursor (0 <x <1, KNNH) formed in Synthesis Example 1, A robust structure was prepared. At this time, the annealing process was performed at a temperature of 500 ° C for 6 hours.
Referring to FIG. 4, it can be confirmed that (Na 1-x K x ) NbO 3 (NKN) phase has a plate shape in the range of 0.35 ≦ y ≦ 0.90. On the other hand, it can be confirmed that the (Na 1-x K x ) NbO 3 (NKN) phase having a plate shape has a rough surface.
5 is an EDX analysis graph for a KNN platy perovskite structure formed according to Example 1. FIG. Here, (a) y = 0.35, (b) y = 0.50, (c) y = 0.80 and (d) y = 0.90.
Referring to FIG. 5, EDX analysis was used to identify the composition for the plate structure of FIG.
y < 0.5, the plate-like structure has a composition similar to (Na 0.4 K 0.6 ) NbO 3 . On the other hand, when y = 0.8 and y = 0.9, it can be seen that K-rich NKN (K-rich NKN) plate structure is formed.
6 is a scanning electron micrograph of a KNN platy perovskite structure formed according to Examples 1 and 2 and Comparative Examples 1 and 2.
Referring to FIG. 6, the annealing process was performed at 600 ° C for 6 hours (a) (Example 1), and at 700 ° C for 6 hours (b) (Comparative Example 1) (C) (Comparative Example 2) in the case where the annealing process was carried out at 600 ° C for 6 hours after the vaporization process was performed at 150 ° C for 12 hours A photograph of each of the NN plate-shaped perovskite structures formed in Example 2 is shown.
It can be confirmed that a perovskite structure deviating from the plate form is formed in Comparative Example 1 and Comparative Example 2 (see b and c).
On the other hand, in the case of Example 1 (a), it can be confirmed that the (Na 1-x K x ) NbO 3 (NKN) plate surfaces having rough surfaces cohere to each other. On the other hand, an additional annealing process is performed to remove water (H 2 O) from the (K 8-8x Na 8x ) Nb 6 O 19 .nH 2 O precursor during the vaporization process. Therefore, the removal of water (H 2 O) together with the subsequent annealing process can suppress the rough surface problem of the KNN platy perovskite structure that occurs during water vaporization in the annealing process.
7A is a transmission electron micrograph of a KNN platy perovskite structure formed according to Example 1. FIG. 7B is a photograph showing an electron scattering pattern for a KNN platy perovskite structure formed according to Example 1. FIG. 7C is a high-performance transmission electron micrograph of a KNN platy perovskite structure formed according to Example 1. FIG.
The KNN platy perovskite structure used in Figs. 7A to 7C corresponds to the case where y = 0.9.
Referring to FIGS. 7A and 7B, the zone axis of the electron scattering pattern is the [110] direction, which indicates that the surface direction of the KNN plate-shaped perovskite structure is also the [110] direction.
On the other hand, referring to FIG. 7C, the inserted numbers are obtained from the image through Fourier transform. And the lattice patterns of the (001) and (110) planes are confirmed. Also, the fast fourier transform (FFT) pattern is in the [110] direction as the zone axis, and the surface direction of the KNN plateau perovskite structure is in the [110] direction.
The present invention can be applied to a nano generator or an eighth generation device for converting the microvibration energy into electric energy or the like by using the method of manufacturing the plate-shaped perovskite structure according to the present invention. Furthermore, the present invention can be applied to the manufacture of piezoelectric devices using a sheet-like perovskite structure produced by a method of manufacturing a sheet-like perovskite structure as a seed material.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.
Claims (5)
Removing water from the precursor through a vaporization process performed at a temperature ranging from 120 to 150 ° C for the precursor; And
And performing an annealing process on the water-removed precursor,
Wherein the annealing process is performed at a temperature ranging from 450 to 700 ° C for 6 to 12 hours.
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| KR1020150080523A KR101650656B1 (en) | 2015-06-08 | 2015-06-08 | Method of manufacturing a platelet perovskite structure |
| PCT/KR2016/003377 WO2016200033A1 (en) | 2015-06-08 | 2016-04-01 | Method for manufacturing layered perovskite structure |
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| KR1020150080523A KR101650656B1 (en) | 2015-06-08 | 2015-06-08 | Method of manufacturing a platelet perovskite structure |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011132118A (en) * | 2009-11-26 | 2011-07-07 | Toyama Prefecture | Anisotropically shaped powder and method for producing the same |
| JP2012188300A (en) * | 2011-03-08 | 2012-10-04 | Toyama Prefecture | Anisotropic-shaped powder and method of manufacturing the same |
| JP2012232862A (en) * | 2011-04-28 | 2012-11-29 | Toyama Prefecture | Anisotropically shaped powder and method for producing the same |
| JP2014012612A (en) * | 2012-07-03 | 2014-01-23 | Hitachi Metals Ltd | Plate-like crystal, method of manufacturing the same and anisotropic-shape powder |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011132118A (en) * | 2009-11-26 | 2011-07-07 | Toyama Prefecture | Anisotropically shaped powder and method for producing the same |
| JP2012188300A (en) * | 2011-03-08 | 2012-10-04 | Toyama Prefecture | Anisotropic-shaped powder and method of manufacturing the same |
| JP2012232862A (en) * | 2011-04-28 | 2012-11-29 | Toyama Prefecture | Anisotropically shaped powder and method for producing the same |
| JP2014012612A (en) * | 2012-07-03 | 2014-01-23 | Hitachi Metals Ltd | Plate-like crystal, method of manufacturing the same and anisotropic-shape powder |
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