Method for producing a sintered silicon nitride base ceramic and said ceramic
First Claim
1. A process of preparation of a silicon nitride based ceramic comprising the steps of combining 60 to 92 mol percent of finely powdered Si3 N4 with at least one member of a first group consisting of MgO, ZnO and NiO and at least one member of a second group consisting of Al2 O3, Cr2 O3, Y2 O3, TiO2 and SnO2, said Si3 N4 powder and said members being in powdered form finer than 300 mesh, the mol ratio of said first group member or members to said second group member or members ranging from 1:
- 9 to 9;
1 and the combined total quantity of said members lying between 8 and 40 mol percent of the combination including said Si3 N4, mixing said powdered materials, forming said mixed powders into a green compact and sintering said green compact at a temperature between 1600°
C and 1800°
C in an inert gas in the absence of applied pressure, the resultant composition consisting essentially of Si3 N4 and members of said first and second groups.
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Abstract
A silicon nitride based ceramic is formed of silicon nitride and at least two metal oxides of such a type that when the metal oxides are heated separately they form a spinel. Combination of said metal oxides and said silicon nitride as fine powders and sintering same at a specified temperature for a specified period of time results in a silicon nitride based ceramic having improved mechanical and chemical properties.
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Citations
2 Claims
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1. A process of preparation of a silicon nitride based ceramic comprising the steps of combining 60 to 92 mol percent of finely powdered Si3 N4 with at least one member of a first group consisting of MgO, ZnO and NiO and at least one member of a second group consisting of Al2 O3, Cr2 O3, Y2 O3, TiO2 and SnO2, said Si3 N4 powder and said members being in powdered form finer than 300 mesh, the mol ratio of said first group member or members to said second group member or members ranging from 1:
- 9 to 9;
1 and the combined total quantity of said members lying between 8 and 40 mol percent of the combination including said Si3 N4, mixing said powdered materials, forming said mixed powders into a green compact and sintering said green compact at a temperature between 1600°
C and 1800°
C in an inert gas in the absence of applied pressure, the resultant composition consisting essentially of Si3 N4 and members of said first and second groups. - View Dependent Claims (2)
- 9 to 9;
Specification
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- Resources
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Current AssigneeKabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
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Original AssigneeKabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
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InventorsMasaki, Hideyuki
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Primary Examiner(s)Arnold, Donald J.
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Assistant Examiner(s)Parrish, John
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Application NumberUS05/408,358Time in Patent Office903 DaysField of Search106/62, 106/65, 106/73.5, 264/65, 264/66, 264/332US Class Current264/668CPC Class CodesC04B 35/584 based on silicon nitrideC04B 35/597 based on silicon oxynitride...
