Claims
- 1. A method of producing a silicon nitride sintered body containing Si.sub.3 N.sub.4 grains comprising the steps of:
- preparing a raw material consisting essentially of
- a) Si.sub.3 N.sub.4 powder as a main component,
- b) 2.7-10 mol % of a rare earth element compound powder, calculated as an oxide of the rare earth element relative to a sum of mol % of Si.sub.3 N.sub.4 and mol % of the rare earth element compound calculated as an oxide of the rare earth element,
- c) 0.5-11 wt. % SiC powder relative to a sum of Si.sub.3 N.sub.4 and the rare earth element compound calculated as an oxide of the rare earth element, and
- d) 0.5-3 wt. % of at least one of a W compound powder or metallic W and a Mo compound powder 14 or metallic Mo relative to a sum of Si.sub.3 N.sub.4 and the rare earth element compound calculated as an oxide of the rare earth element;
- forming the raw material into a shaped body; and
- firing the shaped body at 1,700.degree.-2,100.degree. C. in N.sub.2 atmosphere to substantially crystallize a grain boundary phase of the Si.sub.3 N.sub.4 grains.
- 2. The method of claim 1, wherein the rare earth element of said rare earth element compound is selected from the group consisting of Y and Yb.
- 3. The method of claim 1, wherein said W compound is at least one compound selected from the group consisting of carbides of W, oxides of W, and silicides of W, and said Mo compound is at least one compound selected from the group consisting of carbides of Mo, oxides of Mo, and silicides of Mo.
- 4. The method of claim 1, wherein said shaped body is fired at 1,900.degree.-2,000.degree. C.
Priority Claims (2)
Number |
Date |
Country |
Kind |
2-28170 |
Feb 1990 |
JPX |
|
2-330599 |
Nov 1990 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 07/649,770, filed Jan. 25, 1991, now U.S. Pat. No. 5,096,859.
US Referenced Citations (11)
Divisions (1)
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Number |
Date |
Country |
Parent |
649770 |
Jan 1991 |
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