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EP-4741346-A1 - COMPLEX FLUORIDE POWDER, METHOD FOR PRODUCING COMPLEX FLUORIDE POWDER, AND METHOD FOR MANUFACTURING STRUCTURE

EP4741346A1EP 4741346 A1EP4741346 A1EP 4741346A1EP-4741346-A1

Abstract

A complex fluoride powder includes a plurality of complex fluoride particles containing a complex fluoride that contains an alkali metal. An average particle diameter of the plurality of complex fluoride particles is 1 µm or less, a first weight loss rate when the complex fluoride powder is heated from 30°C to 200°C is 0.5 mass% or more, and a second weight loss rate when the complex fluoride powder is heated from 200°C to 500°C is 1 mass% or less.

Inventors

  • YOSHIOKA, Tatsuro
  • SATO, NATSUKI
  • KURIZOE, NAOKI
  • SAWA, RYOSUKE

Assignees

  • Panasonic Intellectual Property Management Co., Ltd.

Dates

Publication Date
20260513
Application Date
20240704

Claims (7)

  1. A complex fluoride powder comprising a plurality of complex fluoride particles containing a complex fluoride that contains an alkali metal, wherein an average particle diameter of the plurality of complex fluoride particles is 1 µm or less, a first weight loss rate when the complex fluoride powder is heated from 30°C to 200°C is 0.5 mass% or more, and a second weight loss rate when the complex fluoride powder is heated from 200°C to 500°C is 1 mass% or less.
  2. The complex fluoride powder according to claim 1, wherein the plurality of complex fluoride particles have a BET specific surface area of 2 to 200 m 2 /g.
  3. The complex fluoride powder according to claim 1 or 2, wherein the complex fluoride contains fluorine, the alkali metal, and an additional metal, and the additional metal contains at least one metal selected from the group consisting of an alkaline earth metal, aluminum, gallium, indium, zinc, and yttrium.
  4. The complex fluoride powder according to any one of claims 1 to 3, wherein the complex fluoride contains fluorine, the alkali metal, and aluminum.
  5. A method of producing a complex fluoride powder according to any one of claims 1 to 4, comprising: a step of reacting a first metal compound, which is alkali metal fluoride, with a second metal compound including a metal different from the alkali metal fluoride, in a liquid phase to produce a plurality of complex fluoride particles; a step of separating the generated plurality of complex fluoride particles; a step of heating the separated plurality of complex fluoride particles at 200°C or higher; and a step of adding water to the heated plurality of complex fluoride particles.
  6. The method of producing a complex fluoride powder according to claim 5, wherein hydrofluoric acid is not used.
  7. A method of producing a structure comprising a step of pressurizing and heating the complex fluoride powder obtained by the method of producing the complex fluoride powder according to claim 5 or 6.

Description

TECHNICAL FIELD The present invention relates to complex fluoride powder, a method of producing complex fluoride powder, and a method of producing a structure. BACKGROUND ART Conventionally, infrared transmissive windows using inorganic fluoride as a base material have been used for special applications in fields such as academic research and industry, such as window materials for physical and chemical equipment. Patent Literature 1 discloses a Fourier transform infrared spectrophotometer for measuring fluorinated gases in a sample containing corrosive gases, which includes a measuring cell with a cell window composed of one selected from the group consisting of CaF2, BaF2, MgF2, LiF, and ZnSe. CITATION LIST PATENT LITERATURE Patent Literature 1: WO 2019/176624 SUMMARY OF INVENTION There is known a technology for sensing various gases and flames using an infrared detection element and an optical filter for infrared transmission. However, the alkali metal fluorides described above have strong hygroscopicity, and may not be suitable for general applications such as gas sensors and flame detection sensors. In addition, alkali earth metal fluorides have a high melting point of 1200 to 1500°C. Therefore, there is a possibility that a structure having a high infrared transmittance cannot be produced unless an advanced technique requiring a high temperature of at least about 1000°C is utilized. The present invention has been made in view of such problems of the prior art. An object of the present invention is to provide a complex fluoride powder, a method of producing complex fluoride powder, and a method of producing a structure, which can form a structure suitable for applications such as an infrared transmission window for a gas sensor or a flame detection sensor. A complex fluoride powder according to a first aspect of the present invention includes a plurality of complex fluoride particles containing a complex fluoride that contains an alkali metal. An average particle diameter of the plurality of complex fluoride particles is 1 µm or less. A first weight loss rate when the complex fluoride powder is heated from 30°C to 200°C is 0.5 mass% or more. A second weight loss rate when the complex fluoride powder is heated from 200°C to 500°C is 1 mass% or less. A method of producing a complex fluoride powder according to a second aspect of the present invention includes a step of reacting a first metal compound, which is alkali metal fluoride, with a second metal compound including a metal different from the alkali metal fluoride, in a liquid phase to produce a plurality of complex fluoride particles; a step of separating the generated plurality of complex fluoride particles; a step of heating the separated plurality of complex fluoride particles at 200°C or higher; and a step of adding water to the heated plurality of complex fluoride particles. A method of producing a structure according to a third aspect of the present invention includes a step of pressurizing and heating the complex fluoride powder obtained in the method of producing the complex fluoride powder. BRIEF DESCRIPTION OF DRAWINGS [FIG. 1] FIG. 1 is a cross-sectional view schematically illustrating an example of a structure according to the present embodiment.[FIG. 2] FIG. 2 is an enlarged cross-sectional view schematically illustrating another example of the structure according to the present embodiment.[FIG. 3] FIG. 3 is a SEM image of complex fluoride powder obtained in Comparative Example 1 at a magnification of 20,000.[FIG. 4] FIG. 4 is a SEM image of the complex fluoride powder obtained in Comparative Example 2 at a magnification of 20,000.[FIG. 5] FIG. 5 is a SEM image of the complex fluoride powder obtained in Comparative Example 4 at a magnification of 20,000.[FIG. 6] FIG. 6 is a SEM image of the complex fluoride powder obtained in Comparative Example 5 at a magnification of 20,000.[FIG. 7] FIG. 7 is a SEM image of the complex fluoride powder obtained in Comparative Example 6 at a magnification of 20,000.[FIG. 8] FIG. 8 is a SEM image of the complex fluoride powder obtained in Comparative Example 7 at a magnification of 20,000.[FIG. 9] FIG. 9 is a SEM image of the complex fluoride powder obtained in Comparative Example 8 at a magnification of 20,000.[FIG. 10] FIG. 10 is a SEM image of the complex fluoride powder obtained in Comparative Example 9 at a magnification of 20,000.[FIG. 11] FIG. 11 is a SEM image of the complex fluoride powder obtained in Comparative Example 10 at a magnification of 20,000.[FIG. 12] FIG 12 is a SEM image of the complex fluoride powder obtained in Comparative Example 11 at a magnification of 20,000.[FIG. 13] FIG. 13 is a graph illustrating the relationship between the heat treatment temperature and the average particle diameter of the complex fluoride powder to which water is added.[FIG. 14] FIG. 14 is linear transmittance of structures according to Examples 1 to 3 and Comparative Examples 13 and 14.[FIG. 15] FIG. 15