Metal oxide powder and method for the production of the same

Abstract

A powder of a metal oxide except for alpha -alumina, which is constituted of at least six-sided polyhedral particles and has a number-average particle diameter of 0.1-300 mu m and a particle size distribution of 10 or less in terms of D90 / D10 (wherein D10 and D90 represent the particle diameters corresponding to the cumulative amount of, respectively, 10 % and 90 % as determined from the finer particle side in the cumulative size distribution curve for the particles constituting the powder); and a powder of rutile titanium oxide constituted of at least eight-sided polyhedral particles. These powders are reduced in the content of aggregated particles and have a narrow particle size distribution and uniform particle shapes.

Description

[0001] The present invention relates to a metal oxide powder which is used as a raw material powder of an oxide ceramic that is used as a functional material or a structural material, a metal oxide powder which is used in a dispersed state as a filler or a pigment, or a metal oxide powder which is used as a raw material powder for the production of a single crystal or for flame spray coating, and a method for the production thereof.PRIOR ART[0002] In general, an oxide ceramic which is used as a functional material or a structural material is produced through a molding step and a calcination step from a metal oxide powder as a raw material. Properties of the metal oxide powder to be used as the raw material have a large influence on the production steps, and functions and physical properties of the ceramic product. Then, it is highly desired to provide a metal oxide powder having powder properties which are precisely controlled so that they are suitable for an intended application.[0...

AI Technical Summary

Benefits of technology

[0012] Another object of the present invention is to provide a production method which can be generally employed in the production of such metal oxide powder and is excellent industrially.

Problems solved by technology

The produced metal oxide powders have some problems such as formation of agglomerates, nonuniformity in the particles, a wide particle size distribution, and so on, and they are not necessarily satisfactory.

Further, the above production methods themselves have problems such as complicated procedures, problems of apparatuses, costs of raw materials, and so on.

When the average primary particle size of the raw material powder is larger than 0.1 .mu.m, the production of the metal oxide powder containing less agglomerated particles and having the narrow particle size distribution may become difficult.

When a molded material having the bulk density exceeding 40% based on the theoretical density is calcined, a sintering reaction proceeds in the calcination step, whereby grinding is necessitated to obtain the metal oxide powder, and the metal oxide powder having the narrow particle size distribution may not be obtained in some cases.

When the particle size distribution measured by such method is narrow but the powder contains the agglomerated particles, the dispersibility is deteriorated, and such powder is not suitable as an industrial raw material.

When the BET specific surface area is large, the powder contains many agglomerated particles and is not suitable as the industrial raw material.

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