发明授权
- 专利标题: Self-reinforced silicon nitride ceramic of high fracture toughness
- 专利标题(中): 自增强氮化硅陶瓷具有高断裂韧性
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申请号: US290720申请日: 1989-02-28
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公开(公告)号: US4919689A公开(公告)日: 1990-04-24
- 发明人: Aleksander J. Pyzik , Douglas B. Schwarz , William J. Dubensky , Donald R. Beaman
- 申请人: Aleksander J. Pyzik , Douglas B. Schwarz , William J. Dubensky , Donald R. Beaman
- 申请人地址: MI Midland
- 专利权人: The Dow Chemical Company
- 当前专利权人: The Dow Chemical Company
- 当前专利权人地址: MI Midland
- 主分类号: C04B35/593
- IPC分类号: C04B35/593 ; C04B35/645 ; C04B35/80
摘要:
A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powder mixture containing silicon nitride, magnesium oxide, yttrium oxide and calcium oxide under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. A novel silicon nitride ceramic of high fracture toughness is disclosed comprising a .beta.-silicon nitride crystalline phase wherein at least about 20 volume percent of the phase is in the form of whiskers having an average aspect ratio of at least about 2.5; a glassy second phase containing magnesium oxide, yttrium oxide, calcium oxide, and silica in a total amount not greater than about 35 weight percent; and not greater than about 10 weight percent of the total weight as other phases.
公开/授权文献
- US5670480A Method of making polymers having specific properties 公开/授权日:1997-09-23