Premium
Reaction Sintering of Cubic Boron Nitride Using Volatile Catalysts
Author(s) -
Itoh Hideaki,
Takao Hisaaki,
Iwahara Hiroyasu
Publication year - 1993
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1993.tb04032.x
Subject(s) - sintering , catalysis , boron nitride , materials science , activation energy , decomposition , diamond , chemical engineering , boron , indentation hardness , nitride , nuclear chemistry , metallurgy , inorganic chemistry , chemistry , composite material , microstructure , organic chemistry , layer (electronics) , engineering
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 (6.0–7.5 GPa, 1400–1700°C, 0–30 min) using volatile catalysts such as NH 4 NO 3 , NH 4 Cl, and NH 2 NH 2 . Fully dense sintered compacts having a Vickers microhardness of more than 5000 kg/mm 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 2 , H 2 , and/or NH 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.