1895
Frank A. GOOCH, New
Haven, Connecticut: "Art of soldering aluminium", US Patent
597,111; filed March 26, 1895; granted Jan. 11,
1898
("I have found, however, that mixtures of metallic
fluorids with many other suitable substances may be made,
which, while fusing at temperatures
below the fusing point of aluminium, possess the property
in a state of fusion of cleaning the surface
of the aluminium and of protecting it from atmospheric
oxidation")
1910
Stephan JAHN,
of Charlottenburg, Germany, assignor to Aktiengesellschaft Mix
& Genest, Telephon-
und Telegraphenwerke, of Berlin, Germany: "Process
for pickling aluminium and its alloys prior
to galvanizing or coating the same with other
metals", US Patent 1,011,203; filed June 16, 1910; granted
Dec. 12, 1911
(cleaning aluminium in a bath containing e.g. dilute hydrofluoric
acid mixed with ethanol)
1929
Harry V.
CHURCHILL, assignor to Aluminum
Company of America, Pittsburgh, Pa.: "Cleaning composition", US
Patent 1,890,214; filed May
18, 1929; granted Dec. 6, 1932
("I have discovered that an aqueous solution of
an organic fruit acid in which
is also contained a small amount of an alkali fluoride
will, when brought to a temperature somewhat near the boiling point
of water, completely remove the stain and discoloration
on aluminum articles if the articles are but dipped into
the solution for a few moments and then rinsed with
hot or warm water. I have further discovered
that it is the presence of the fluoride
in the solution which completely eliminates the
objection to the former use of inorganic fruit acids of
this nature, namely, the fluoride appears to
remove the resultant scum or
general discoloration which is produced by the action of the
fruit acid on the metal.")
1931
Pierre PRIER,
Paris, France: "Process of protecting light metals
against corrosion", US Patent 1,957,354; filed April 27, 1931 (France),
April 26, 1932 (U.S.), granted May 1, 1934
(uses
fluovanadates, fluosilicates, fluorides)
1942
Wayne E.
WHITE, assignor to Aluminum Company of
America, Pittsburgh, Pa.: "Method for
cleaning aluminum", US Patent 2,431,595; filed
Aug. 6, 1942, granted Nov. 25, 1947
("It is my discovery
that molten ammonium fluoride
(NH4F) will remove the various surface
coatings and films, including the heaviest of
oxide coatings, from aluminum surfaces")
1943
Mike
A. MILLER, Wayne E.
WHITE, assignors to
Aluminum Company of America, Pittsburgh, Pa.: "Method
of removing oxide coating from aluminum surfaces", US
Patent 2,399,134; filed Feb. 24, 1943; granted April
23, 1946
("... a satisfactory solution may
be prepared by mixing a strong aqueous solution of
hydrogen fluoride with the alcoholic compound")
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