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EP0171819A2
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High toughness silicon nitride sintered body and process for producing the same
Assignee: Hitachi Ltd
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Filing: 1985-08-20
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Granted: —
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Expires: 2005-08-20
Abstract
Abstract A high toughness silicon nitride sintered body comprises silicon nitride as a main component and at least one member selected from the group consisting of silicides and carbides in the form of plate particles, of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W. In the sintered body, the longer diameter d 1 of principal plane of plate of the plate particles and the shorter diameter d 2 of the same plane has a relation of d 1 /d 2 < 10, and the thickness of plate of the plate particles is 1/5 or below of d 2 .
Inventors
- 👤 Hiroshi Sakamoto
- 👤 Tadahiko Miyoshi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 07:06
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584; C04B35/593; C04B35/622; C04B35/626; C04B35/62605; C04B35/62645; C04B35/62665; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3217; C04B2235/3224; C04B2235/3225; C04B2235/38; C04B2235/3817; C04B2235/3839; C04B2235/3843; C04B2235/3847; C04B2235/3891; C04B2235/50; C04B2235/52; C04B2235/5292; C04B2235/54; C04B2235/5418; C04B2235/5427; C04B2235/5436; C04B2235/5445; C04B2235/70; C04B2235/96
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
76 words
A high toughness silicon nitride sintered body, characterized in that said sintered body comprises silicon nitride as a main component and at least one member selected from the group consisting of silicides and carbides in the form of plate particles, of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, the thickness of plate of said plate particles being 1/5 or below of the shorter diameter of principal plane of plate of the plate particles.-
Claim 2
Dependent Claim
76 words
A high toughness silicon nitride sintered body, characterized in that said sintered body comprises silicon nitride as a main component and at least one member selected from the group consisting of silicides and carbides in the form of plate particles, of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, the thickness of plate of said plate particles being 1/5 or below of the shorter diameter of principal plane of plate of the plate particles.-
Claim 3
Dependent Claim
59 words
A high toughness silicon nitride sintered body according to Claim 1, wherein the longer diameter of principal plane of plate of the plate particles is larger than the diameters of other particles also present in the sintered body but smaller than 100 µm, and the plate particles occupy 2 to 13 % of the volume of the sintered body.
Claim 4
Dependent Claim
48 words
A high toughness silicon nitride sintered body according to Claim 1, wherein the ratio (d l /d 2 ) of the longer diameter d l of principal plane of plate of the plate particles to the shorter diameter d 2 of the same plane is 10 or below.
Claim 5
Dependent Claim
44 words
.4. A high toughness silicon nitride sintered body according to Claim 1, wherein the plate particles consist of at least one member selected from the group consisting of silicides and carbides of V, Nb and Ta as well as carbides of Mo and W.
Claim 6
Dependent Claim
137 words
A process for producing a high toughness silicon nitride sintered body according to anyone of Claims 1 to 4, which comprises the steps of: subjecting at least one silicide or carbide of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W to melting, cooling and mechanical grinding to obtain a powder consisting of plate particles, subjecting the powder to sieving to select those plate particles of which the thickness of plate is 1/5 or below of the shorter diameter of principal plane of plate; mixing the selected plate particles with a sintering aid and a silicon nitride powder and then subjecting the resulting mixture to pressure molding to obtain a molding, and sintering the molding at such a temperature that the plate particles in the molding are substantially not melted, reacted and changed in their properties.
Claim 7
Dependent Claim
32 words
A process for producing a high toughness silicon nitride sintered body according to Claim 5, wherein the sintering temperature of the molding is in a range of 1,550 °C to 1,900 °C.
Claim 8
Dependent Claim
29 words
A process for producing a high toughness silicon nitride sintered body according to Claim 6, wherein the sintering temperature is in a range of 1,700 °C to 1,800 °C.
Claim 9
Dependent Claim
36 words
A process for producing a high toughness silicon nitride sintered body according to anyone of Claims 5 to 7, wherein the sintering time of the molding is in a range of 30 minutes to 2 hours.
Claim 10
Dependent Claim
29 words
A process for producing a high toughness silicon nitride sintered body according to Claim 8, wherein the sintering time is in a range of 30 minutes to 1 hour.
Claim 11
Dependent Claim
26 words
The use of a high toughness silicon nitride sintered body according to anyone of Claims 1 to 4 for producing gas turbine blades or engine parts.
References Cited (Backward Citations)
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