Dense shaped articles consisting of polycrystalline hexagonal bo

Details Dense shaped articles consisting of polycrystalline hexagonal bo Dense shaped articles consisting of polycrystalline hexagonal bo

1984-08-31

1987-01-06

Swisher, Nancy

Stock material or miscellaneous articles

Composite

Of b, n, p, s, or metal-containing material

428698, 423290, B32B 516, B32B 1502, B32B 2102, B32B 2702

Patent

active

046346406

ABSTRACT:
The invention is a shaped article of boron nitride having a density of at least 95% of the theoretical density which consists of polycrystalline hexagonal boron nitride in the form of a homogeneous isotropic microstructure and which has been manufactured from pure boron nitride powder without the concomitant use of sintering aids by isostatic hot-pressing in a vacuum-tight casing at temperatures of from about 1200.degree. to 1500.degree. C. under a pressure of from about 50 to 300 MPa. Boron nitride powders having a free boric oxide content of not more than 1.0% by weight and having a specific surface area of from 5 to 30 m.sup.2 /g are used as starting material. The powders either are filled into prefabricated casings consisting of steel or glass and densified by vibration or are preshaped to form green bodies having pores open to the surface and then placed in prefabricated casings or coated with a material which forms a vacuum-tight casing. The powders or the preshaped green bodies in the vacuum-tight casings are then subjected to an isostatic hot-pressing process in a high-pressure zone using an inert gas such as argon or nitrogen, as the pressure-transfer medium.

REFERENCES:
patent: 2808314 (1957-10-01), Taylor
patent: 3241918 (1966-03-01), Lenihan, Jr. et al.
patent: 4072797 (1978-02-01), Gass et al.
patent: 4096297 (1978-06-01), Pappis et al.
patent: 4148863 (1979-04-01), Farafontov et al.
patent: 4148964 (1979-04-01), Fedoseer et al.
patent: 4440828 (1984-03-01), Resneau et al.
patent: 4469802 (1984-09-01), Endo et al.
patent: 4551316 (1985-11-01), Iizuka
EP 0040552, Nov. 1981, DeBeers.
CA 97: 43096f, Mattsson et al.

Affiliated with

Also associated with

Rating

Dense shaped articles consisting of polycrystalline hexagonal bo does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Dense shaped articles consisting of polycrystalline hexagonal bo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dense shaped articles consisting of polycrystalline hexagonal bo will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-683724