Appeal No. 2002-0895
Application No. 09/402,552
Boxall teaches [a] method for producing a coating
having a titanium diboride of at least 80% by weight.
Column 4, lines 40-55 and column 2, line 50 through column
3, line 10 (the coating can be 100% titanium diboride). A
coating of about 10 mils (about .25 mm) can be applied.
Column 4, lines 45-55. The coating is applied by plasma
spraying. Column 4, lines 40-55. The porosity of the
coating is less than 10% by volume. Column 3, lines 35-45
(the coating is desired to be nonporous). The titanium
diboride is to be sprayed at using argon/hydrogen gas.
Column 4, lines 40-55. The spray powder is of 100% titanium
diboride, so the oxygen content of the powder to be sprayed
would be less than 1% by weight.
The examiner states that Boxall does not expressly state that its
plasma spraying is carried out in an inert atmosphere and its
spray powder has a mean particle size of from 10 to 55
micrometer. See the Answer, page 4. To remedy this deficiency,
the examiner relies on the disclosures of Mills and Gruenr.
Mills teaches that “throughout the coating industry,” plasma
spraying is carried out in an inert atmosphere and/or low
pressure chamber. See page 364, column 1. The inert atmosphere
chamber restricts the formation of undesired oxide, minimizes
changes in chemistry of the coating and reduces environmental
problems, such as dust and noise. See page 364, columns 2 and 3.
Mills teaches (page 364, column 2) that:
In any good inert gas chamber, oxygen levels can be
easily maintained below 30 ppm. Metal powders tend to
cleanup when sprayed in an inert gas chamber by the
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