Appeal No. 95-3366
Application No. 08/113,550
not relate to heat treating" (page 13 of Brief). The reference
specifically states that the disclosed process is for
thermochemical treatment of metals.
We also disagree with appellants' argument that European
'550 "does not teach an ionizing gas that is reactive with the
workpiece (claim 13)" (page 13 of Brief). Like appellants, the
reference forms a plasma from nitrogen gas under the same process
parameters. We note the disclosure at page 12 of appellants'
specification that "[t]he use of nitrogen as the ionizing gas can
result in not only heating but also formation of a hard nitride
layer at the surface of the workpiece." As for the discontinuous
pulses of claim 15, this much is suggested at page 4 of the
reference, first paragraph. Regarding the claim 33 requirement
of providing at least two workpieces, we find that it would have
been prima facie obvious for one of ordinary skill in the art to
treat any number of workpieces that can be practically
accommodated in a reactor.
For the rejection over Dexter our analysis is essentially
the same. Dexter discloses the pulsed plasma thermochemical
treatment of a workpiece and evidences that it was known in the
art to use a high-voltage electrical discharge to generate a
continuous plasma which envelopes the workpiece and heats it to
the necessary temperature (see column 1). Although the reference
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