Appeal No. 1999-0761 4
Application No. 08/174, 957
acidic solution of pH 2 or less containing chloride ions, followed by etching in an
aqueous alkaline solution of pH 13 or more.” The reference however, fails to teach, “a
single step [etching] process,” the presence of a chelating agent or even a specific
teaching that the etching is applied to an aluminum alloy within the scope of the claimed
subject matter.
With respect to the disclosure of Lowenheim, we find numerous disclosures
regarding the utilization of alkaline cleaners and etchants. We find that Lowenheim
discloses in reference to cleaning metals in general that, “[n]o single alkali makes a
good cleaner; a combination of alkalis with appropriate soaps or surfactants, chelating
agents, and other ingredients is necessary for maximum effectiveness.” See
Lowenheim, page 75. We conclude that Lowenheim at that site refers generally to the
cleaning of metals, as opposed to the etching of metals and refers to metals generally in
the absence of specific reference to aluminum alone, let alone aluminum alloys. We
further find a discussion of chelating agents on page 76 of Lowenheim wherein it is
stated that, “chelating agents . . . can soften water and tie up many metal ions. They
are used in many nonphosphated cleaners, etchants for aluminum, alkaline derusting
and descaling agents, and in electrocleaners.” No reference, however, is made to
aluminum alloys in general or to the specific aluminum alloys of the claimed subject
matter. Indeed, where the reference specifically refers to aluminum and its alloys,
Lowenheim, pages 89-91, alloying elements such as magnesium are disclosed. See,
Lowenheim, page 90. Lowenheim, however, states therein that, “[c]leaning and
conditioning pretreatments are necessary, as for all metals; vapor degreasing or other
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