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US 8,133,830 B2Granted
Silicon nitride sintered compact and sliding member using the same
AssigneesKabushiki Kaisha Toshiba, Toshiba Materials Co., Ltd.
InventorsMinoru Takao, Michiyasu Komatsu
Life of this patent
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Abstract
A silicon nitride sintered compact contains silicon nitride grains, and a sintering aid component in a range of 2 to 15 mass %. The silicon nitride grains include needle crystal grains each having a long diameter L of 10 μm or less and a ratio (L/S) of the long diameter L to a short diameter S of 5 or more, by 50% or more in area ratio in a crystalline structure of the silicon nitride sintered compact. The silicon nitride sintered compact is used as a sliding member like a bearing ball (2).
Claims8
A sliding member comprising:
- a silicon nitride sintered compact containing silicon nitride grains, and a sintering aid component in a range of not less than 2 mass % and not more than 15 mass %,
- wherein the silicon nitride grains include needle crystal grains each having a long diameter L of 10 μm or less and a ratio of the long diameter L to a short diameter S (L/S) of 5 or more, wherein an area ratio of the needle crystal grains in a crystalline structure of the silicon nitride sintered compact is in a range of not less than 50% and not more than 80%,
- wherein a maximum diameter of voids existing in the silicon nitride sintered compact is 3 μm or less,
- wherein a number of the voids is five or less in a region of 30×30 μm, and
- wherein the sliding member is a bearing ball.
2 more elements
Dependencies are inferred from the claim text.