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Effect of B 2 O 3 and hBN Crystallinity on cBN Synthesis
Author(s) -
Choi JunYoup,
Kang SukJoong L.,
Fukunaga O.,
Park JongKu,
Eun K. Y.
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.tb03976.x
Subject(s) - crystallinity , crystallization , amorphous solid , materials science , crystallography , chemical engineering , chemistry , engineering
Four kinds of BN powders—amorphous BN with B 2 O 3 , partially crystallized BN without B 2 O 3 , well‐crystallized hBN with B 2 O 3 , and well‐crystallized hBN without B 2 O 3 —were prepared to determine the effect of B 2 O 3 on the crystallization of amorphous BN and the effect of BN crystallinity on the formation of cBN under high pressure (4–5 GPa) and at high temperature (1350–1450°C). The amorphous BN with B 2 O 3 easily crystallized and transformed to cBN in the presence of A1N catalyst, while the partially crystallized BN without B 2 O 3 did not. The well‐crystallized hBN transformed very slowly to cBN without B 2 O 3 , in contrast to fast transformation with B 2 O 3 . It is thus found that the transformation from hBN to cBN in the presence of AIN catalyst is determined by the degree of BN crystallinity as well as the presence of B 2 O 3 . Cubic BN can be synthesized only from crystallized hBN under the experimental conditions used. The formation of cBN from amorphous BN is possible through its prior crystallization, which can occur in the presence of B 2 O 3 .