Abrasive tool making process – material – or composition – With inorganic material
Patent
1992-01-24
1992-11-03
Group, Karl
Abrasive tool making process, material, or composition
With inorganic material
51309, 501 95, 501 97, 501 98, C09B 3558
Patent
active
051605082
ABSTRACT:
A process for preparing a self-reinforced silicon nitride ceramic body of high fracture toughness comprising hot-pressing a powder mixture containing silicon nitride, a densification aid such as sodium oxide, a conversion aid such as lanthanum oxide and a compound, such as gallium oxide, which enhances growth of .beta.-silicon nitride whiskers-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 and high fracture strength 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 the densificaton aid, the conversion aid, the compound which enhances growth of .beta.-silicon nitride whiskers, and an amount of silica; and not greater than about 10 weight percent of the total weight as other phases. The glassy phase may also include a minor amount, e.g., up to 5.0 weight percent, based upon total weight of the ceramic, of aluminum nitride or boron nitride. The glassy phase optionally includes an amount of a secondary reinforcing material such as silicon carbide whiskers.
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), Buijan
patent: 4218257 (1980-08-01), Oda et al.
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: 4511525 (1985-04-01), Tsuge et al.
patent: 4543345 (1985-09-01), Wei
patent: 4603116 (1986-07-01), Smith et al.
patent: 4609633 (1986-02-01), Fukuhara et al.
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: 4879263 (1989-11-01), Komeya et al.
patent: 4883776 (1989-11-01), Pyzik et al.
patent: 4919689 (1990-04-01), Pyzik et al.
patent: 4923829 (1990-05-01), Yasutomi et al.
patent: 5021372 (1991-06-01), Pyzik et al.
patent: 5091347 (1992-02-01), Pyzik et al.
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).
Beaman Donald R.
Dubensky William J.
Pyzik Aleksander J.
Pyzik Barbara M.
Rossow Harold E.
Group Karl
Howard D. R.
The Dow Chemical Company
LandOfFree
Self-reinforced silicon nitride ceramic of high fracture toughne does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-reinforced silicon nitride ceramic of high fracture toughne, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-reinforced silicon nitride ceramic of high fracture toughne will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2049217