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US 5,178,809 AGranted
Process for producing silicon nitride sintered material
AssigneeNGK Insulators, Lts.
InventorsAkira Takahashi, Keiichiro Watanabe
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Abstract
Powders of carbides are mixed with a silicon nitride powder and powders of rare earth element oxides to obtain a mixture. The mixture is shaped and fired in a casing in a nitrogen atmosphere of 1,700.degree.-2,100.degree. C. under the conditions specified by the following formula: (0.025x-0.05)<y.ltoreq.0.1x wherein x is a firing time (hr) and y is the weight (g) of shaped material to be filled into casing divided by the internal volume (cc) of the casing.
Claims6
A process for producing a silicon nitride sintered material, which comprises:
- mixing raw materials consisting essentially of a silicon nitride powder, powders of rare earth element oxides and powders of carbides;
- shaping the resulting mixture to obtain a shaped material;
- and firing the shaped material in a casing in a nitrogen atmosphere of 1,700.degree.-2,100.degree. C. under the conditions specified by the following formula:
- (0.025x-0.05)<y.ltoreq.0.1x
- wherein x is a firing time, in hours, and y is the weight, in grams, of shaped material to be filled into the casing divided by the internal volume, in cubic centimeters, of the casing.
2 more elements
Dependencies are inferred from the claim text.