EP0199178A1
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Process for preparation of sintered silicon nitride
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1986-04-08
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Granted: —
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Expires: 2006-04-08
Abstract
Abstract Disclosed is a process for preparation of a sintered silicon nitride. The process comprises the steps of: mixing a powder of silicon nitride with a powder of sintering agent; compacting the obtained mixture; and sintering the compacted mixture in a non-oxidizing atmosphere. The feature of the process is that the powder of sintering agent includes a powder mixture of oxide and/or hydroxide of at least two kinds of metals which has been prepared by co-precipitation. Due to use of the co-precipitated powder as sintering agent, it is possible to obtain a sintered silicon nitride having an excellent strength and uniformity in quality. The obtained sintered silicon nitride is preferably used as an engineering ceramic.
Inventors
- 👤 Akira C/O Itami Works Of Sumitomo Yamakawa
- 👤 Masaya C/O Itami Works Of Sumitomo Miyake
- 👤 Takao C/O Itami Works Of Sumitomo Nishioka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 23:26
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/5935
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
69 words
A process for preparing a sintered silicon nitride comprising the steps of: mixing a powder of silicon nitride with a powder of sintering agent; compacting the obtained mixture; and sintering the compacted mixture in a non-oxidizing atmosphere, the process being characterized in that said powder of sintering agent includes a powder mixture of oxide and/or hydroxide of at least two kinds of metals which has been prepared by co-precipitation.
Claim 2
Dependent Claim
69 words
A process for preparing a sintered silicon nitride comprising the steps of: mixing a powder of silicon nitride with a powder of sintering agent; compacting the obtained mixture; and sintering the compacted mixture in a non-oxidizing atmosphere, the process being characterized in that said powder of sintering agent includes a powder mixture of oxide and/or hydroxide of at least two kinds of metals which has been prepared by co-precipitation.
Claim 3
Dependent Claim
33 words
A process as claimed in Claim 1, wherein the co-precipitated powder includes oxide and/or hydroxide of metals selected from the group consisting of Mg, Al, Si, Sc, Y, lanthanide, Ti, Zr and Hf.
Claim 4
Dependent Claim
41 words
A process as claimed in Claim 1, wherein the sintering agent is mixed in an amount of 1.0 to 50 wt% calculated in terms of the oxide contained therein on the basis of the total weight of the sintered silicon nitride.
Claim 5
Dependent Claim
27 words
A process as claimed in claim 3, wherein the co-precipitated powder includes oxide and/or hydroxide of metals selected from the group consisting of Zr, Y and lanthanide.
Claim 6
Dependent Claim
31 words
A process as claimed in Claim 4, wherein the co-precipitated powder includes oxide and/or hydroxide of Zr and at least one element selected from the group consisting of Y and lanthanide.
Claim 7
Dependent Claim
88 words
A process as claimed in Claim 5, wherein the co-precipitated powder includes ZrO. and oxide of at least one element selected from the group consisting of Y and lanthanide, and the content of Zr0 2 being 1 to 25 vol% on the basis of the total volume of the sintered silicon nitride and the content of the oxide of Y or lanthanide being 0.5 to 10 wt% calculated in terms of the amount of the element on the basis of the total weight of the sintered silicon nitride.
Claim 8
Dependent Claim
36 words
A process as claimed in Claim 6, wherein Zr0 2 is cubic crystal which has been stabilized with at least one member selected from the group consisting of CaO, MgO and Y 2 O 3 .
Claim 9
Dependent Claim
42 words
A process as claimed in Claim 7, wherein, in order to provide the sintering agent, hydroxides of Zr and Y are co-precipitated and the co-precipitate is then burned to provide a powder of cubic ZrO2 stabilized with Y 2 3 O .
Claim 10
Dependent Claim
42 words
A process as claimed in Claim 5, further incorporating to the mixture of 1 to 15 wt% of at least one element selected from the group consisting of the elements of IVa (except Zr), Va and Via groups of the Periodic Table.
Claim 11
Dependent Claim
44 words
A process as claimed in Claim 9, wherein the element of selected from IVa (except Zr), Va and Via group of the Periodic Table is added to the mixture in the form of anyone of carbide, nitride, carbonitride, oxide and the solid solution thereof.
Claim 12
Dependent Claim
50 words
A process as claimed in Claim 10, wherein oxide of at least one element selected from the group consisting of IVa (except Zr), Va and Via groups of the Periodic Table is added to the mixture in the co-precipitated form with oxide or hydroxide of Zr and Y or lanthanide.
Claim 13
Dependent Claim
40 words
A process as claimed in Claim 1, wherein the hydroxides of metal have been prepared by adjusting pH of an aqueous solution containing a watersoluble metal chloride, metal nitrate or organic metal salt to thereby co-precipitate the metal hydroxides therefrom.
Claim 14
Dependent Claim
20 words
A process as claimed in Claim 12, further burning the metal hydroxides to thereby provide a co-precipitate of metal oxides.
Claim 15
Dependent Claim
21 words
A process as claimed in Claim 1, wherein the mean particle size of the co-precipitated powder is smaller than 2 microns.
Claim 16
Dependent Claim
16 words
A process as claimed in Claim 1, wherein the sintering is conducted under a depressurized condition.
Claim 17
Dependent Claim
16 words
A process as claimed in Claim 1, wherein the sintering is conducted under a pressurized condition.
References Cited (Backward Citations)
JPS5771871A
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EP0100380A1
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