Reaction sintering of cubic boron nitride using volatile catalysts

Journal Article · Mon Nov 01 00:00:00 EST 1993 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1993.tb04032.x· OSTI ID:5521623

Itoh, Hideaki; Takao, Hisaaki; Iwahara, Hiroyasu ^[1]

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1. Nagoya Univ. (Japan). Synthetic Crystal Research Lab.

Reaction sintering behavior of cBN, which is accompanied by the transformation from hBN to cBN in the presence of 30 wt% diamond seed grains, was investigated under high pressure conditions using volatile catalysts such as NH[sub 4]NO[sub 3], NH[sub 4]Cl, and NH[sub 2]NH[sub 2]. Fully dense sintered compacts having a Vickers microhardness of more than 5,000 kg/mm[sup 2] were prepared with no residual catalytic solid components. The activation energy for the conversion from hBN to cBN was 200-230 kJ/mol. Adsorbed N[sub 2], H[sub 2], and/or NH[sub x] components which were formed by decomposition of these catalysts during high pressure and temperature treatments, would have a favorable kinetic effect on cBN formation from hBN and its simultaneous sintering.

• OSTI ID: 5521623
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 76:11; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON NITRIDES
SINTERING
CATALYSTS
PRESSURE DEPENDENCE
TEMPERATURE DEPENDENCE
VOLATILE MATTER
BORON COMPOUNDS
FABRICATION
MATTER
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication