JPS58165208A - Method of producing orientation sodium niobate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing oriented NaNbO3 films. NaNbO3 has a perovskite structure similar to BaTio3, which exhibits a high dielectric constant, and also exhibits ferroelectricity, making it a promising material as a dielectric voltage material.

Generally, a ceramic sintered body is an aggregate of microcrystals, grain boundaries exist, and the crystal axes of each microcrystal are arranged randomly, so that its physical properties indicate the average value of each crystal axis. It is known that in oxide dielectric materials, dielectric constant and piezoelectricity increase due to crystal orientation, and mechanical strength increases due to reduction of crystal grain boundaries. Crystal orientation technology for ceramic materials has recently become an important issue from an industrial perspective. Methods for bringing anisotropy to the electromagnetic properties of sintered ceramic materials include (1) forming in a magnetic field, (1) utilizing topotaxial effects (so), and hot processing by hot pressing. The method requires that the material be ferromagnetic or ferrimagnetic, and in (1), a part of the starting material must have significant shape anisotropy. Furthermore, since the method of (Cao) involves pressurization at high temperatures, it has the drawback of not being suitable for mass production, and furthermore, it is difficult to produce ceramic thin films. In this respect, the present invention is completely different from conventional methods, and is a method of forming an oriented NaN'bO3 film for effectively equalizing electrical properties such as dielectric constant.

In the oriented NaNbO3 film forming method of the present invention, NaNbO3 or a mixture containing a small amount of a fluxing agent such as boron oxide, borax, sodium silicate, etc. is deposited in a platinum nozzle at 73°C.
The melt is completely melted at a temperature of 00 to 7,700°C, and the molten material is rolled and super-quenched between two quenching plates sandwiched between rubber rows as shown in Figure 1, thereby forming an oriented ribbon. A sodium niobate film is obtained. The quenching treatment of a ceramic melt depends on conditions such as material composition, but it either vitrifies it as it is or precipitates a crystalline phase. Even if it crystallizes, it is unlikely to become oriented. It is thought that the crystal orientation phenomenon according to the present invention is related to the fact that unidirectional solidification is performed during the ultra-quenching process of the ceramic melt. That is, the quenching effect was greater on the surface portion of the film that was in contact with the two metal quench plates than on the central portion, and as a result, a temperature gradient of .'1 occurred in the film thickness direction, making unidirectional solidification possible. As a result, it is presumed that the crystal orientation occurs in the direction of the normal force of film formation.

As an example, NaNb with v% of boron oxide added
O3 powder total platinum/X iv in 1/C/A; 00”Cl
An oriented NaNbO3 ceramic film with good uniformity could be obtained by ultra-quenching while rolling with a quenching plate with a thickness of 200 mol/l. Unoriented NaNbO3
In order to compare the synthesized powder and the oriented NaNbO3 ultra-quenched film, their X-ray diffraction patterns are shown in FIGS. 2 and 3. Figure 2 shows NaNb03 crystal powder obtained by solid-phase reaction, showing an X-ray diffraction pattern characteristic of a perovskite structure.

This crystal is distorted into an orthorhombic crystal at room temperature and can be indexed using a large unit cell, but here we have expressed it using an ordinary unit cell for ease of understanding. Figure 3 shows oriented NaNb
This is an X-ray diffraction pattern of an ultra-quenched film of O3, automatically recorded under the same X-ray diffraction conditions as for the synthetic powder. From the comparison between Figures 2 and 3, Na oriented in the (001) plane
Since it is a NbO3 film, it is clear that the angle is 1111°.

Simple explanation of the drawing '1.1 FIG. 7 is a schematic diagram of an apparatus for producing an ultra-quenched film.

FIG. 2 is an X-ray diffraction pattern of NaN1)03 powder, shown for comparison with an oriented sample. FIG. 3 is an X-ray diffraction pattern of an oriented NaNbO3 ultra-quenched film obtained according to the present invention.

Patent applicant Director of the Agency of Industrial Science and Technology Stone tablet im - Engraving of drawings (no change in content) Procedural amendment (trial) 57 Special Technical Special No. gO June 10, 1980 Commissioner of the Japan Patent Office Haruki Shimada 11 [n June 1957 1
48 Submission/Display of the incident Showa! 7 Year Patent Application No. 1/22.2λ Name of Invention Relationship with Case Patent Applicant Address (〒700) 3-chome/Kasumigaseki, Chiyoda-ku, Tokyo/No. Kogyogijutsuincho Ishijika Seiichi Name (//41) Kogyo Director of the Agency of Technology Seigu Ishiban Designated Agent Sep 1980 78-1 B Subject of amendment (1) Brief description of drawings in the specification (2) Drawing 7
Contents of amendment ■(1) Memorandum (
4. Correct the entire text in the brief description column of the drawing as shown in the attached sheet.

(2) Reproduction of the specification (drawings) (no changes to the contents) FIG. 1 is a schematic diagram of the ultra-quenching apparatus used in carrying out the present invention. The explanation of each number in the figure is as follows.

／・・・・・・Platinum nozzle (outer diameter g y x m, inner diameter 4 mm,
Length 10011) 2... Electric furnace (silicon carbide heating element) 3...
...Metal plate (stainless steel) G...Rubber roller S...Wire rope B...Rewinder orientation sample shown for comparison.

111: Figure 3 shows the oriented Na, NbO3 ultra-steeply obtained according to the present invention.
1N(DXliA@J'!4.Ap -=yT:A6・
The x i'' bending patterns in Figures 2 and 3 were automatically recorded using copper as the anticathode.

Claims (1)

[Claims] Add a small amount of sodium niobate (Nal'JbO3) or a fluxing agent such as boron oxide, borax, sodium phosphate, or sodium silicate to it, melt it completely, and quench the ceramic melt between two metal sheets. drop it between the boards,
A method for producing oriented niobium ceramics in the form of a thin film, which is characterized by instantaneous rolling and ultra-quenching.