Ceramic member and manufacturing method for the same

• US 7,582,367 B2
• Filed: 09/27/2005
• Issued: 09/01/2009
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Kato, Tsutomu, Nobori, Kazuhiro, Aihara, Yasufumi, Matsuda, Hiroto
• Primary Examiner(s): Zimmerman; John J.
• Assistant Examiner(s): Austin; Aaron
• Application Number:
  US11/236,223
• Publication Number:
  US 20060073349A1
• Time in Patent Office: 1,435 Days
• Field of Search: None
• US Class Current: 428/701
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3246 Stabilised zirconias, e.g. YSZ or cerium stabilised zirconia
• CPC Class Codes: C04B 2235/422 Carbon
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/608 Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/6562 Heating rate
• CPC Class Codes: C04B 2235/6567 Treatment time
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/786 Micrometer sized grains, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 2235/9661 Colour
• CPC Class Codes: C04B 2237/064 based on alumina or aluminates
• CPC Class Codes: C04B 2237/34 Oxidic
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/119 with zirconium oxide
• CPC Class Codes: C04B 35/505 : based on yttrium oxide
• CPC Class Codes: C04B 35/5626 : based on tungsten carbides
• CPC Class Codes: C04B 35/6365 : Cellulose or derivatives thereof
• CPC Class Codes: C04B 35/645 : Pressure sintering
• CPC Class Codes: C04B 37/001 : directly with other burned ceramic articles
• CPC Class Codes: C04B 37/005 : consisting of glass or ceramic material

Abstract

A ceramic member is provided including a base including an alumina sintered body, an yttria sintered body formed on the alumina sintered body, an intermediate layer including yttrium and aluminum formed between the alumina sintered body and the yttria sintered body, and a metallic member buried in the intermediate layer of the base. A difference between the thermal expansion coefficient of the alumina sintered body and that of the yttria sintered body is equal to or less than about 0.50×10⁻⁶/K, and the thermal expansion coefficient of the alumina sintered body is greater than the thermal expansion coefficient of the yttria sintered body. The alumina sintered body, the intermediate layer, the yttria sintered body, and the metallic member are formed into an integrated sintered body, and the content of yttria in the yttria sintered body is 99 wt % or more.

Claims

1. A ceramic member comprising:

a base including an alumina sintered body, a yttria sintered body formed on the alumina sintered body and exposed to a corrosive gas, and an intermediate layer including yttrium and aluminum formed between the alumina sintered body and the yttria sintered body; and

a metallic member buried in the intermediate layer of the base;

wherein a difference between a thermal expansion coefficient of the alumina sintered body and a thermal expansion coefficient of the yttria sintered body is equal to or less than about 0.50×

10<sup>−

6</sup>/K;

wherein the thermal expansion coefficient of the alumnina sintered body is greater than the thermal expansion coefficient of the yttria sintered body;

wherein the alumina sintered body, the intermediate layer, the yttria sintered body, and the metallic member are formed into an integrated sintered body; and

wherein a content of yttria in the yttria sintered body is 99 wt % or more.

2. The ceramic member according to claim 1, wherein the intermediate layer includes a plurality of layers each having different yttrium and aluminum contents with respect to one another.

3. The ceramic member according to claim 1, wherein a difference between a thermal expansion coefficient of the metallic member and the thermal expansion coefficient of the alumina sintered body, and a difference between the thermal expansion coefficient of the metallic member and the thermal expansion coefficient of the yttria sintered body are equal to or less than about 3×

10<sup>−

6</sup>/K.

4. The ceramic member according to claim 1, wherein the metallic member is a least one of an electrostatic electrode, a resistance heating element, and an RF electrode.

5. The ceramic member according to claim 1, wherein a volume resistivity of the yttria sintered body is equal to or greater than about 1×

10¹⁵ Ω

·

cm.

6. The ceramic member according to claim 1, wherein a thickness of the yttria sintered body is about 0.3 to about 0.5 mm.

7. The ceramic member according to claim 1, further comprising:

a terminal connecting the metallic member to a power supply member; and

a connecting member buried in the base, joined with the metallic member and the terminal, and connecting the metallic member to the terminal.

8. The ceramic member according to claim 7, wherein a difference between a thermal expansion coefficient of the connecting member and the thermal expansion coefficient of the alumina sintered body is equal to or less than about 2×

10<sup>−

6</sup>/K.

9. The ceramic member according to claim 7, wherein the connecting member includes at least one of platinum and niobium.

10. The ceramic member according to claim 7, wherein a distance between a joint surface of the connecting member and the metallic member and a joint surface of the connecting member and the terminal is equal to or greater than about 1 mm.

11. A method of manufacturing a ceramic member, comprising the steps of:

forming an alumina sintered body;

forming a yttria sintered body exposed to a corrosive gas, wherein a content of yttria in the yttria sintered body is 99 wt % or more;

forming a metallic member; and

integrating the alumina sintered body, the yttria sintered body and the metallic member;

wherein an intermediate layer including yttrium and aluminum is formed between the alumina sintered body and the yttria sintered body;

wherein the metallic member is buried in the intermediate layer;

wherein a difference between a thermal expansion coefficient of the alumina sintered body and a thermal expansion coefficient of the yttria sintered body is equal to or less than about 0.50×

10<sup>−

6</sup>/K; and

wherein the thermal expansion coefficient of the alumina sintered body is greater than the thermal expansion coefficient of the yttria sintered body.

12. The method according to claim 11, wherein

the step of forming the alumina sintered body includes a step of forming an alumina presintered body;

wherein the metallic member is formed on one of the alumina sintered body and the alumina presintered body;

wherein the step of forming the yttria sintered body includes forming a yttria compact on the metallic member; and

wherein the one of the alumina sintered body and the alumina presintered body, the metallic member, and the yttria compact are integrated by sintering.

13. The method according to claim 11, wherein

the step of forming the yttria sintered body includes a step of forming a yttria presintered body;

wherein the metallic member is formed on one of the yttria sintered body and the yttria presintered body;

wherein the step of forming the alumina sintered body includes forming an alumina compact on the metallic member; and

wherein the one of the yttria sintered body and the yttria presintered body, the metallic member, and the alumina compact are integrated by sintering.

14. The method according to claim 11, wherein the yttria sintered body is formed using a yttria powder that is calcined at about 400°

C. or greater.

15. The method according to claim 11, wherein the yttria sintered body is formed using a yttria powder having a water content that is equal to or less than about 1%.

16. The method according to claim 11, wherein the yttria sintered body is formed by sintering a yttria compact having a density that is equal to or less than about 2 g/cc.