JPH04317412A - Production of copper oxide-based conductive ceramics - Google Patents

Abstract

PURPOSE:To produce copper oxide-based conductive ceramics at a relatively low temp. from the raw material available easily and inexpensively. CONSTITUTION:A mixture of the copper nitrate, copper chloride, indium nitrate and lead nitrate is heated at 300-550 deg.C to produce copper oxide-based conductive ceramics shown by the general formula [1] Cu6(InxPby)O8-xCl. The ceramics are appropriately used as the material for various electrodes and heating elements, and are of great use as the material for an oxide superconductor in the field where technology is remarkably improved in recent years.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for manufacturing conductive oxide ceramics, and in particular, copper oxide conductive ceramics that can be manufactured by heating at relatively low temperatures using easily and inexpensively available raw materials. The present invention relates to a method for manufacturing ceramics.

0002

2. Description of the Related Art Conductive ceramics have been used in a wide range of fields as electrodes, heating elements, etc., taking advantage of their excellent properties such as corrosion resistance and heat resistance, which are unique to ceramics. for example,
RuO2 is used for electrode materials, thermal heads of thermal transfer printers, etc. Furthermore, other applications of conductive ceramics include the application of ITO ceramics to transparent electrodes and the application of PLZT ceramics to optical switches, and the field of application thereof is expanding.

In the general formula [1] in the claims, x=0,
The compound represented by the chemical formula Cu6O8PbCl, where y=1 and z=0, is known as a naturally occurring mineral crystal under the name mardocite. A known method for artificially synthesizing mardocite is to synthesize it from a mixed aqueous solution of copper chloride and lead hydroxide through a hydrothermal reaction, but the reproducibility of the reaction is poor, and Pb2 CuCl2
Since it is only produced as a by-product of (OH)4, it has been difficult to artificially synthesize a single phase.

0004

[Problems to be Solved by the Invention] As described above, conductive ceramics are used in a wide range of fields, and because their usefulness is emphasized, a method for manufacturing conductive ceramics more cheaply and easily is always desired. ing. The method for manufacturing conductive ceramics represented by the general formula [1] in the claims was invented in view of these circumstances,
The purpose of this invention is to industrially advantageously produce mardocite-type compounds, which have conventionally been difficult to synthesize, by heating them at relatively low temperatures using readily available raw materials.

[0005]

[Means for Solving the Problems] A method for manufacturing a copper oxide-based conductive ceramic according to the present invention is a conductive copper oxide-based ceramic represented by the following general formula [1]: Cu6 (In
x Pby ) O8-z Cl --- [1] However, x+y=1 0≦x<1 0<y≦1 0≦z≦1 A method for producing copper nitrate, copper chloride, indium nitrate, and A mixture consisting of lead nitrate at 300℃ to 550℃
It is characterized by heating.

The present invention will be explained in detail below. Conductive ceramics are obtained by first mixing predetermined amounts of copper nitrate, copper chloride, indium nitrate, and lead nitrate, and then heating the resulting mixture at 300 to 550°C. If the heating temperature exceeds 550°C, CuO and In2O3, which are insulating ceramics, will be decomposed and produced, and the proportion of conductive ceramics will decrease, and if the heating temperature is higher than that, all of them will become insulating ceramics, which is not preferable. . On the other hand, if the heating temperature is less than 300°C, the decomposition reaction of nitrates will not proceed efficiently.

[0007] The heating time is appropriately selected from about 30 minutes to 15 hours, and the heating can be carried out using a conventional heating device such as an electric furnace. The method for mixing raw material compounds of copper nitrate, copper chloride, indium nitrate, and lead nitrate is as follows:
A method of pulverizing and mixing each raw material compound with a ball mill etc.
Alternatively, a method may be adopted in which the aqueous solutions of the raw material compounds are mixed and then evaporated to dryness to remove water.

[0008]

[Operation] The conductive ceramic obtained by the production method of the present invention is recognized to be a cubic mardocite type crystal belonging to the space group Fm3m from the pattern of its X-ray diffraction spectrum. This crystal includes a cubic crystal in which oxygen is partially deficient, and the oxidation number of copper is thought to be a mixed valence of +2 to +3, which is presumed to contribute to electrical conductivity.

As described above, according to the present invention, conductive ceramics can be easily produced using inexpensive and easily available raw materials such as nitrates and chlorides. Furthermore, according to the present invention, it is possible to replace some of the lead atoms in the mardocite crystal with In at any desired ratio. By doing so, it is possible to easily obtain ceramics with even lower resistivity and excellent conductivity.

0010

[Examples] The present invention will be explained in more detail with reference to Examples below.

<Example 1> 7.824 g of copper nitrate trihydrate
, 1.104 g of cupric chloride dihydrate, and 1.10 g of lead nitrate.
A mixture of 0.073g and 350g of
It was heated at ℃ for 5 hours. As a result, a copper oxide-based conductive ceramic having a cubic X-ray diffraction pattern as shown in FIG. 1 was obtained. From this X-ray diffraction spectrum, it was confirmed that Cu6 PbO8 Cl was produced in this example. The resistivity of the conductive ceramic thus obtained was 1 Ω·cm at room temperature.

<Example 2> A mixture consisting of 7.4 g of copper nitrate trihydrate, 1.044 g of cupric chloride dihydrate, 1.149 g of indium nitrate trihydrate, and 0.406 g of lead nitrate. was heated at 520°C for 20 minutes. As a result, Figure 2
A copper oxide conductive ceramic having a cubic X-ray diffraction pattern as shown in FIG. Based on this X-ray diffraction spectrum, Cu6 (In0.4 P
b0.6) It was confirmed that O8Cl was generated. The specific resistance of the conductive ceramic thus obtained was 10 mmΩ·cm at room temperature.

[0013]

[Effects of the Invention] As detailed above, according to the method for manufacturing copper oxide conductive ceramics of the present invention, copper oxide conductive ceramics with excellent crystallinity and uniformity can be easily produced compared to conventional methods. It is possible to manufacture

[0014] This copper oxide-based conductive ceramic can be suitably used as a raw material for various electrodes and heating elements, and is also useful as a raw material for producing oxide superconductors, which have seen remarkable technological progress in recent years. be. Therefore, the significance of the present invention, which provides such materials easily and inexpensively, is extremely profound.

[0015]

[Brief explanation of drawings]

FIG. 1 is a graph showing an X-ray diffraction spectrum of a copper oxide-based conductive ceramic obtained in Example 1 of the present invention.

FIG. 2 is a graph showing the X-ray diffraction spectrum of the copper oxide conductive ceramic obtained in Example 2 of the present invention.

Claims (1)

[Claims] [Claim 1] Copper oxide-based conductive material represented by the following general formula [1], which is characterized by heating a mixture of copper nitrate, copper chloride, indium nitrate, and lead nitrate at 300°C to 550°C. Ceramics manufacturing method. Cu6 (Inx Pby)O8-z Cl---[
1] However, x+y=1 0≦x<1 0<y≦1 0≦z≦1