Appeal No. 2005-1934 Page 2
Application No. 10/022,357
INTRODUCTION
Claim 2 is directed to a method of manufacturing a catalytic oxide anode. According to
the specification, catalytic oxide anodes formed from ruthenium oxide or iridium oxide applied
to a titanium base metal (RuO2/Ti or IrO2/Ti) have been known in the art (specification, pp. 3-6).
According to the specification, these anodes have been conventionally sintered at temperatures
lower than 550 °C because oxidation of the titanium base metal occurs at higher temperatures
increasing the resistance of the oxide anode surface and reducing the oxide anode activity
(specification, pp. 3-4). However, higher sintering temperatures are desirable in order to obtain
optimal decomposition of organic substances when the anode is used to remove organic
substances from water (specification, p. 4). Appellants are able to sinter their anode at
temperatures above 600 °C because they form a TiO2-screening layer between the titanium base
metal and the catalytic oxide anode. The screening layer prevents the oxidation of the titanium
base metal during the high temperature sintering operation (specification, p. 1 and p. 12). The
screening layer is a metal oxide layer of TiO2, SnO2, RuO2, or IrO2. The TiO2-screening layer is
itself sintered at 450-550 °C. Claim 2 is illustrative of the subject matter on appeal:
2. A method for manufacturing a catalytic oxide anode using high
temperature sintering, wherein a TiO2-screening layer, which is a metal oxide
layer of TiO2, SnO2, RuO2, or IrO2, sintered at 450 to 550°C, is added between
titanium support and a surface of the oxide anode, coated with a precursor
solution of RuCl3 or IrCl3 in hydrochloric acid according to a brushing or dipping
method, dried at 60°C for 10 min, thermally treated at 250 to 350°C for 10 min,
and finally sintered at 600 to 700°C for 1 to 2 hours, said TiO2-screening layer
serving as an [sic] valve metal oxide for preventing the activity of the anode from
being lowered owing to the oxidation of a titanium base metal caused upon
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