Process for production of scandia-stabilized zirconia sheet, scandia-stabilized zirconia sheet obtained by the process, and scandia-stabilized zirconia sintered powder

Patent metadata

Field	Value
Publication number	US-9601795-B2
Application number	US-201013503154-A
Country	US
Kind code	B2
Filing date	Oct 22, 2010
Priority date	Oct 23, 2009
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The present invention relates to a method of producing a scandia-stabilized zirconia sheet. The method includes the steps of: (1) pulverizing a scandia-stabilized zirconia sintered body to obtain a sintered scandia-stabilized zirconia powder having an average particle diameter (De), determined by a transmission electron microscope, in the range of 0.3-1.5 μm, and an average particle diameter (Dr), determined by a laser scattering method, in the range of 0.3-3.0 μm, where a ratio of Dr/De is at least 1.0-2.5; (2) preparing a slurry containing the sintered scandia-stabilized zirconia powder and an unsintered zirconia powder, where a percentage of the sintered scandia-stabilized zirconia powder to a sum of the sintered scandia-stabilized zirconia powder and the unsintered zirconia powder in the slurry is at least 2 mass % and at most 40 mass %; (3) molding the slurry into a green sheet; and (4) sintering the green sheet.

First claim

The invention claimed is:

1. An electrolyte sheet for a solid oxide fuel cell comprising a scandia-stabilized zirconia sheet, comprising a sintered mixture of a zirconia unsintered powder and the scandia-stabilized zirconia sintered powder, the scandia-stabilized zirconia sintered powder comprising:
more than 0.3 μm and not more than 1.5 μm of an average primary particle diameter (De) determined by a transmission electron microscope;
more than 0.3 μm and not more than 3.0 μm of an average secondary particle diameter (Dr) determined by a laser scattering method using a dispersion obtained by adding 0.01-0.5 mass % of the power to 100 cm 3 of an aqueous solution containing 0.2 mass % of sodium metaphosphate and dispersing the powder by supersonic wave for 3 minutes; and
more than 1.0 and not more than 2.5 of a ratio (Dr/De) of the average particle diameter determined by the laser scattering method to the average particle diameter determined by the transmission electron microscope;
wherein the scandia-stabilized zirconia sheet further comprises not less than 0.35 GPa of a three-point flexural strength; and not less than 98% of a relative density relative to a theoretical density; and,
wherein the scandia-stabilized zirconia sintered powder is not less than 2 mass % and not more than 40 mass % of a sum of the zirconia unsintered powder and the scandia-stabilized zirconia sintered powder combined.

2. A solid oxide fuel cell, comprising the electrolyte sheet of claim 1 .

3. The electrolyte sheet of claim 1 , wherein a rest angle of the scandia-stabilized zirconia sintered powder is not less than 15° and not more than 35°.

4. The electrolyte sheet of claim 1 , wherein the Scandia-stabilized zirconia sintered powder contains a cubic system and/or a rhombohedral system.

Assignees

• Hata Kazuo
• Aikawa Norikazu
• Nippon Catalytic Chem Ind

Inventors

• Hata Kazuo
• Aikawa Norikazu

Classifications

• C04B35/6261

  Milling · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C04B2235/3246

  Stabilised zirconias, e.g. YSZ or cerium stabilised zirconia · CPC title

• C04B2235/3298

  Bismuth oxides, bismuthates or oxide forming salts thereof, e.g. zinc bismuthate · CPC title

• C04B35/6263

  characterised by their solids loadings, i.e. the percentage of solids · CPC title