Compositions: ceramic – Ceramic compositions – Refractory
Patent
1990-08-15
1992-02-25
Dixon, Jr., William R.
Compositions: ceramic
Ceramic compositions
Refractory
501 96, 501 97, 501 98, C04B 3502
Patent
active
050913476
ABSTRACT:
Prepare a self-reinforced silicon nitride ceramic body of high fracture toughness by hot-pressing a powder mixture containing silicon nitride and three other components under conditions such that densification and the in situ formation of .beta.-silicon nitride whiskers having a high aspect ratio occur. The other components are silicon dioxide as a densification aid, a conversion aid such as yttrium oxide and a compound, such as calcium oxide, which enhances growth of .beta.-silicon nitride whiskers. The resultant silicon nitride ceramic has a .beta.-silicon nitride cyrstalline phase, at least 20 volume percent of which is in the form of whiskers or elongated grains having an average aspect ratio of at least about 2.5, and a glassy second phase. The glassy phase contains the silicon dioxide, the conversion aid and the compound which enhances growth of .beta.-silicon nitride whiskers. The glassy phase may also include a minor amount of aluminum nitride or boron nitride.
REFERENCES:
patent: 3950464 (1976-04-01), Masaki
patent: 4004937 (1977-01-01), Masaki
patent: 4025351 (1977-05-01), Masaki
patent: 4046580 (1977-09-01), Ishii et al.
patent: 4097293 (1978-06-01), Komeya et al.
patent: 4119689 (1978-10-01), Prochazka et al.
patent: 4179301 (1979-12-01), Buljan
patent: 4218257 (1980-08-01), Oda
patent: 4227842 (1980-10-01), Samanta et al.
patent: 4279657 (1981-07-01), Greskovich
patent: 4296065 (1981-10-01), Ishii et al.
patent: 4323325 (1982-04-01), Samanta et al.
patent: 4406668 (1983-09-01), Sarin et al.
patent: 4407970 (1983-10-01), Komatsu et al.
patent: 4511402 (1985-04-01), Miura et al.
patent: 4511525 (1985-04-01), Tsuge et al.
patent: 4543345 (1985-09-01), Wei
patent: 4603116 (1986-07-01), Smith et al.
patent: 4609633 (1986-09-01), Fukuhara
patent: 4652276 (1987-03-01), Burden
patent: 4699890 (1987-10-01), Matsui
patent: 4717693 (1988-01-01), Wittmer
patent: 4734234 (1988-03-01), Sterzel
patent: 4753764 (1988-06-01), Kamijo et al.
patent: 4870036 (1989-09-01), Yeh
patent: 4883776 (1989-11-01), Pyzik et al.
patent: 4891342 (1990-01-01), Yokoyama
patent: 4919689 (1990-04-01), Pyzik et al.
patent: 4920085 (1990-04-01), Yoshida et al.
patent: 4923829 (1990-05-01), Yasutomi
Akihiko Tsuge et al., Journal of The American Ceramics Society, 58 323-326 (1975).
F. F. Lange, Journal of The American Ceramics Society, 62, 1369-1374 (1983).
Chemical Abstract 105:157787w (1986).
Pyzik Aleksander J.
Pyzik Barbara M.
Dixon Jr. William R.
Hollenbeck Sue
Howard D. R.
The Dow Chemical Company
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