Process and composition for desmutting surfaces of aluminum and its alloys

Claim 2

A liquid solution composition of matter consisting essentially of water and: (A) an oxidizing inorganic acid; (B) phosphoric acid; (C) sulfuric acid; (D) a source of simple fluoride ions; (E) a source of complex fluoride ions; (F) an organic carboxylic acid having from 1-10 carbon atoms per molecule; and (G) a source of manganese in its +4 oxidation state,

Claim 3

A composition according to claim 1, wherein the inorganic oxidizing acid is nitric acid, the source of simple fluoride ions is hydrofluoric acid, the source of complex fluoride ions is fluosilicic acid, the organic carboxylic acid is acetic acid, and the manganese in its +4 oxidation state is produced in situ by oxidizing Mn +2 ions with hydrogen peroxide.

Claim 4

A composition according to claim 2, wherein the concentration of oxidizing inorganic acid is from about 151 to about 251 g/L, the ratio by weight of simple fluoride ions to oxidizing inorganic acid is from about 0.103:1 to about 0.114:1, the ratio by weight of complex fluoride ions to oxidizing acid is from about 0.011:1 to about 0.016:1, the ratio by weight of sulfuric acid to oxidizing inorganic acid is from about 0.45:1 to about 0.55:1, the ratio by weight of phosphoric acid to oxidizing inorganic acid is from about 0.086:1 to about 0.095:1, the ratio by weight of carboxylate groups to oxidizing inorganic acid is from about 0.082:1 to 0.153:1, the ratio by weight of manganese to oxidizing inorganic acid is from 0.047:1 to 0.087:1, the points of free acid are from 8.8 to 13.8, and the points of total acid are from 10.2 to 15.2.

Claim 5

A composition according to claim 3, wherein the concentration of oxidizing inorganic acid is from about 174 to about 228 g/L, the ratio by weight of simple fluoride ions to oxidizing inorganic acid is from about 0.105:1 to about 0.112:1, the ratio by weight of complex fluoride ions to oxidizing acid is from about 0.013:1 to about 0.015:1, the ratio by weight of sulfuric acid to oxidizing inorganic acid is from about 0.47:1 to about 0.52:1, the ratio by weight of phosphoric acid to oxidizing inorganic acid is from about 0.088:1 to about 0.093:1, the ratio by weight of carboxylate groups to oxidizing inorganic acid is from about 0.105:1 to 0.128:1, the ratio by weight of manganese to oxidizing inorganic acid is from 0.023-0.027, the points of free acid are from 10.3 to 12.3, and the points of total acid are from 11.7 to 13.7.

Claim 6

A composition according to claim 1, said composition having been prepared by the steps of: (I) from 1-5 parts by weight of about 35% aqueous hydrogen peroxide with 70 parts of by weight of a solution consisting of 440 to 70 parts by weight of deionized water, 427 to 712 parts by weight of concentrated nitric acid (42° Baume), 35-58 parts by weight of 75% aqueous orthophosphoric acid (H 3 PO 4 ), 25 to 42 parts by weight of glacial acetic acid, and 71-118 parts by weight of a 50% by weight aqueous solution of Mn(NO 3 ) 2 ; (II) allowing the mixture prepared in step (I) to sit until the evolution of visible gas bubbles therefrom has ceased; and (III) mixing with the composition from the end of step (II) 30 parts by weight of another composition consisting of 407 to 507 parts by weight of concentrated sulfuric acid (66 Baume), 418 to 227 parts by weight of deionized water, 136 to 151 parts by weight of 70% aqueous hydrofluoric acid, and 40 to 58 parts by weight of 25% aqueous solution of fluosilicic acid (H 2 SiF 6 ).

Claim 7

A composition according to claim 5, said composition having been prepared by the steps of: (I) mixing 2 parts by weight of 35% aqueous hydrogen peroxide with 70 parts of by weight of a solution consisting of 267.3 parts by weight of deionized water, 561.0 parts by weight of concentrated nitric acid (42° Baume), 45.4 parts by weight of 75% aqueous orthophosphoric acid (H 3 PO 4 ), 33.3 parts by weight of glacial acetic acid, and 93.0 parts by weight of 50% aqueous solution of Mn(NO 3 ) 2; (II) allowing the mixture prepared in step (I) to sit until the evolution of visible gas bubbles therefrom has ceased; and (III) mixing with the composition from the end of step (II) 30 parts by weight of another composition consisting of 457 parts by weight of concentrated sulfuric acid (66° Baume), 351.2 parts by weight of deionized water, 144.0 parts by weight of 70% aqueous hydrofluoric acid, and 47.7 parts by weight of 25% aqueous solution of fluosilicic acid (H 2 SiF 6 ).

Claim 8

An aqueous solution composition of matter, consisting essentially of 442-70 parts by weight of water, 427 to 712 parts by weight of concentrated nitric acid (42° Baume), 35-58 parts by weight of 75% aqueous orthophosphoric acid (H 3 PO 4 ), 25 to 42 parts by weight of glacial acetic acid, and 71-118 parts by weight of a 50% by weight aqueous solution of Mn(NO 3 ) 2 .

Claim 9

An aqueous solution composition of matter, consisting essentially of 442-70 parts by weight of water, 427 to 712 parts by weight of concentrated nitric acid (42° Baume), 35-58 parts by weight of 75% aqueous orthophosphoric acid (H 3 PO 4 ), 25 to 42 parts by weight of glacial acetic acid, and 71-118 parts by weight of a 50% by weight aqueous solution of Mn(NO 3 ) 2 .

Claim 10

An aqueous solution composition of matter, consisting essentially of 407 to 507 parts by weight of concentrated sulfuric acid (66° Baume), 418 to 227 parts by weight of deionized water, 136 to 151 parts by weight of 70% aqueous hydrofluoric acid, and 40 to 58 parts by weight of 25% aqueous solution of fluosilicic acid (H 2 SiF 6 ).

Claim 11

An aqueous solution composition of matter, consisting essentially of 407 to 507 parts by weight of concentrated sulfuric acid (66° Baume), 418 to 227 parts by weight of deionized water, 136 to 151 parts by weight of 70% aqueous hydrofluoric acid, and 40 to 58 parts by weight of 25% aqueous solution of fluosilicic acid (H 2 SiF 6 ).

Claim 12

A process for desmutting, deoxidizing, or both desmutting and deoxidizing an aluminum surface, said process comprising contacting said aluminum surface with a composition according to claim 6 for a sufficient time at a sufficient temperature to be effective for desmutting or deoxidizing.

Claim 13

A process for desmutting, deoxidizing, or both desmutting and deoxidizing an aluminum surface, said process comprising contacting said aluminum surface with a composition according to claim 5 for a sufficient time at a sufficient temperature to be effective for desmutting or deoxidizing.

Claim 14

A process for desmutting, deoxidizing, or both desmutting and deoxidizing an aluminum surface, said process comprising contacting said aluminum surface with a composition according to claim 4 for a sufficient time at a sufficient temperature to be effective for desmutting or deoxidizing.

Claim 15

A process for desmutting, deoxidizing, or both desmutting and deoxidizing an aluminum surface, said process comprising contacting said aluminum surface with a composition according to claim 3 for a sufficient time at a sufficient temperature to be effective for desmutting or deoxidizing.

Claim 16

A process for desmutting, deoxidizing, or both desmutting and deoxidizing an aluminum surface, said process comprising contacting said aluminum surface with a composition according to claim 2 for a sufficient time at a sufficient temperature to be effective for desmutting or deoxidizing.

Claim 17

A process for desmutting, deoxidizing, or both desmutting and deoxidizing an aluminum surface, said process comprising contacting said aluminum surface with a composition according to claim 1 for a sufficient time at a sufficient temperature to be effective for desmutting o deoxidizing.

Claim 18

A process according to claim 14, wherein the aluminum surface is the surface of an aluminum alloy selected from the group consisting of alloys with from 5-12% by weight of silicon and the temperature during the process is in the range from 10° to 35° C.

Claim 19

A process according to claim 13, wherein the aluminum surface is the surface of an aluminum alloy selected from the group consisting of alloys with from 5-12% by weight of silicon and the temperature during the process is in the range from 10° to 35° C.

Claim 20

A process according to claim 12, wherein the aluminum surface is the surface of an aluminum alloy selected from the group consisting of alloys with from 5-12% by weight of silicon and the temperature during the process is in the range from 10° to 35° C.

Claim 21

A process according to claim 11, wherein the aluminum surface is the surface of an aluminum alloy selected from the group consisting of alloys with from 5-12% by weight of silicon and the temperature during the process is in the range from 10° to 35° C.

Claim 22

A process according to claim 10, wherein the aluminum surface is the surface of an aluminum alloy selected from the group consisting of alloys with from 5-12% by weight of silicon and the temperature during the process is in the range from 10° to 35° C.

Claim 23

A process according to claim 9, wherein the aluminum surface is the surface of an aluminum alloy selected from the group consisting of alloys with from 5-12% by weight of silicon and the temperature during the process is in the rang from 10° to 35° C.