Cleaning aluminum workpieces
AssigneeAlcan International Limited
InventorsPeter Karl Ferdinand Limbach, Armin Kumpart, Nigel Cleaton Davies, Jonathan Ball
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Abstract
A method of cleaning an Al workpiece comprises a.c. anodising the workpiece in an acidic electrolyte capable of dissolving aluminium oxide and maintained at a temperature of at least 70.degree. C. under conditions such that the surface of the workpiece is cleaned with any oxide film thereon being non-porous and no more than about 20 nm thick.
Claims10
A method of cleaning an Al or Al alloy workpiece which method comprises anodising the workpiece at a chosen a.c. voltage X (expressed in rms V) in an acidic electrolyte containing phosphoric acid or sulphuric acid capable of dissolving aluminium oxide and maintained at a temperature of at least 80.degree. C. for high magnesium alloys and at least 85.degree. C. for all other alloys under conditions such that the surface of the workpiece is cleaned with any oxide film thereon being non-porous and having a thickness Y (expressed in nm) wherein Y is not more than about half X.
A method of cleaning an Al or Al alloy workpiece which method comprises anodising the workpiece at a chosen a.c. voltage in an acidic electrolyte containing phosphoric or sulphuric acid capable of dissolving aluminium oxide and maintained at a temperature of at least 80.degree. C. for high magnesium alloys and at least 85.degree. C. for all other alloys under conditions such that the surface of the workpiece is cleaned with any oxide film thereon being non-porous and having a thickness of not more than about 20 nm.
Dependencies are inferred from the claim text.