Electrochemical treatment of aluminum surfaces with an aqueous solution of hydrochloric acid and gluconic acid

Claim 2

A process for treatment of aluminum to provide a roughened surface thereon suitable for lithographic uses which comprises electrolytically etching the aluminum with a mixture of hydrochloric acid and gluconic acid.

Claim 3

The process of claim 1 wherein said hydrochloric acid has a concentration equivalent to 1 to 5 parts per 100 parts treating solution of a 37% by weight hydrochloric acid solution in parts by volume and said gluconic acid has a concentration equivalent to 1 to 3 parts per 100 parts treating solution of a 50% by weight gluconic acid solution in parts by volume.

Claim 4

The process of claim 2 wherein said equivalent concentrations are 3 parts by volume hydrochloric acid (37% by weight) and 1 part by volume gluconic acid (50% by weight) per 100 parts by volume treating solution.

Claim 5

The process of claim 2 wherein said aluminum is electrolytically treated by immersing at least two pieces of aluminum into said solution at a distance of 3.8 to 15.3 cm apart as opposite electrodes of a 50-60 cycle alternating current source and flowing an alternating current therebetween at a rate of from 2.6 to 15.6 amperes per square decimeter for a period of from 1 to 10 minutes and at a temperature of from 4°-33° Centigrade.

Claim 6

An acidic electrolyte for etching of aluminum therein to render the metal suitable for lithographic uses by roughening of the surface which comprises a mixture of hydrochloric and gluconic acids.

Claim 7

An acidic electrolyte for etching of aluminum therein to render the metal suitable for lithographic uses by roughening of the surface which comprises a mixture of hydrochloric and gluconic acids.

Claim 8

The electrolyte of claim 5 wherein the concentration of said hydrochloric acid is equivalent to 1 to 5 parts per 100 parts electrolyte of a 37% by weight hydrochloric acid in parts by volume and said gluconic acid has a concentration equivalent to 1 to 3 parts per 100 parts treating solution of a 50% by weight gluconic acid solution in parts by volume.