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US 4,251,384 AGranted
Aluminum polishing compositions
AssigneeAlbright & Wilson Limited
InventorTerence R. Rooney
Life of this patent
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Abstract
Aluminium polishing solutions containing phosphoric, nitric and sulphuric acids provide etched finishes if the proportion of sulphuric acid is increased. The invention inhibits such etching by addition to the bath of an aromatic ring compound in which at least 2 hetero atoms are conjugated with the ring such as benztriazole.
Claims9
An aluminium polishing solution consisting essentially of
- (a) phosphoric and sulphuric acid in a relative proportion of from 1:2 to 3:1, phosphoric acid having a specific gravity of 1.75 to 98 percent sulphuric acid and together constituting at least 90 percent of the total composition;
- (b) nitric acid in a proportion by weight of from 1.2 to 4.2 percent as 100 percent nitric acid;
- (c) dissolved copper in a concentration of from 0.01 to 0.2 percent by weight;
- (d) dissolved aluminium in a concentration of between zero and saturation;
- (e) from 0.05 percent to 0.7 percent by weight of an organic etch inhibitor which is an aromatic organic compound soluble in said solution and having an aromatic 6-member ring selected from the group consisting of benzene, pyridine, pyrazine, benzoquinone, and melamine rings and at least 2 hetero atoms selected from the group consisting of nitrogen, oxygen and sulphur atoms conjugated with said aromatic ring;
- and
- (f) the balance substantially of water.
4 more elements
Dependencies are inferred from the claim text.