Appeal No. 2003-1525
Application 09/462,876
Suzuki does not disclose obtaining the low pressure phase
boron nitride by reducing and nitriding boron oxide or boric acid
in the presence of carbon and nitrogen. However, Suzuki
indicates that the low pressure phase boron nitride can be hBN,
provided that it is highly pure so that it produces the desired
high purity sintered cBN (col. 2, lines 44-57; col. 3, lines 11-
12; col. 4, lines 23-26). Thus, Suzuki would have fairly
suggested, to one of ordinary skill in the art, use of any hBN
which is known to be sufficiently pure to produce a high purity
sintered body. One such hBN is that of Kawasaki which, Kawasaki
teaches, can be used to form high purity sintered hBN (col. 3,
lines 17-19). Kawasaki’s hBN is made by mixing boric acid and
melamine in an atmosphere containing steam, and crystallizing the
resulting melamine borate particles to produce hBN. Melamine is
a compound used by the appellants to provide the carbon and
nitrogen used in reducing and nitriding boric acid (example 1).
The appellants argue that “Suzuki et al. employ pBN to
obtain a cBN sintered compact which is highly oriented in
the (111) structure and, hence, exhibits anisotropic properties
in strength and direction, with very low strength” (brief,
page 12). Suzuki mentions measuring (111) diffraction intensity
when determining the amount of low pressure phase boron nitride
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