Appeal No. 94-3737
Application 07/796,932
separates the silicon atoms of the silicon carbide from the
carbon atoms thereof and the carbon atoms are converted to
synthetic diamond, the thus-produced synthetic diamond is cooled
to ambient temperature while it is maintained in the diamond
stable region of the diamond graphite phase diagram; and the
thus-produced synthetic diamond is isolated from the reaction
product; the improvement which comprises heating the silicon
carbide to a temperature of up to 1,200EC but below the
temperature at which a non-diamondaceous form of elemental carbon
is converted to synthetic diamond under the conditions employed,
in a matrix which contains a reactant which chemically reacts
selectively with the silicon atoms of the silicon carbide and
which forms a frangible reaction product when cooled, whereby the
carbon atoms which are thus separated from the silicon carbide
are converted to synthetic diamond at a temperature below that
required to convert elemental carbon to synthetic diamond under
the conditions employed; and isolating the synthetic diamond from
the frangible reaction product by physical means.
In the rejection of the appealed claims, the examiner relies
upon the following references:
Jurewicz et al. 5,128,080 July 7, 1992
(Jurewicz) (filed Aug. 30, 1990)
Shipton 971,943 Oct. 7, 1964
(Great Britain patent specification)
Appellant’s claimed invention is directed to a process for
producing synthetic diamonds which comprises heating silicon
carbide in a matrix which contains a material that chemically
reacts with the silicon atoms of the silicon carbide. The
reacting material can be, inter alia, a metal oxide, a metal salt
or a metal hydroxide.
Page 1 of appellant’s specification acknowledges that a
commercial method developed in the 1950s by General Electric
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