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US 4,397,721 AGranted
Pickling of aluminum
AssigneeFokker B.V.
InventorsRobertus Exalto, Adriaan Kwakernaak
Life of this patent
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Abstract
Articles of aluminum are pickled by placing them as anodes into a sulfuric acid bath in the absence of chromic acid or bichromate and connecting them by a short-circuit connection to a carbon cathode placed in the same bath. The process also excludes the application of an anodic control voltage.
Claims11
A pickling process for aluminum articles, comprising the steps of:
- (a) providing a pickling bath consisting essentially of sulfuric acid;
- (b) positioning two electrodes, viz. an anode and a cathode, into said pickling bath, said anode comprising an aluminum article to be pickled and said cathode comprising at least one carbon body;
- (c) interconnecting said anode and said cathode by means of an external short-circuit connection;
- and
- (d) maintaining said short-circuit connection during a period of time sufficient to cause complete pickling of said aluminum article.
2 more elements
A pickling process for aluminum articles, comprising the steps of:
- (a) providing a pickling bath consisting essentially of sulfuric acid in a concentration of about 100 g/l said bath having a temperature between 40.degree. and 60.degree. C.;
- (b) positioning two electrodes, viz. an anode and a cathode, into said pickling bath, said anode comprising an aluminum article to be pickled and having a surface area ratio of about 6 to said cathode, and said cathode comprising at least one carbon body;
- (c) interconnecting said anode and said cathode by means of an external short-circuit connection, and
- (d) maintaining said short-circuit connection during a period of time sufficient to achieve a complete pickling of said aluminum article.
1 more element
A pickling process for aluminium articles, comprising the steps of:
- (a) providing a pickling bath consisting essentially of sulfuric acid in a concentration of about 200 g/dm.sup.3, said bath having a temperature of about 40.degree. C.;
- (b) positioning two elelctrodes, viz. an anode and a cathode, into said pickling bath, said anode comprising an aluminium article to be pickled and having a surface area ratio of more than 6 to said cathode, said cathode comprising at least one carbon body;
- (c) interconnecting said anode and said cathode by means of an external short-circuit connection;
- and
- (d) maintaining said short-circuit connection during a period of time sufficient to achieve complete pickling of said aluminium article.
2 more elements
Dependencies are inferred from the claim text.