Methods and compositions for acid treatment of a metal surface

Abstract

The invention relates to compositions and methods that are useful in etching a metal surface. In particular, the invention relates to novel acid compositions and methods of using such compositions in etching a metal surface, preferably an aluminum surface prior to anodizing to dissolve impurities, imperfections, scale, and oxide. The compositions are effective in maintaining their etching capacity and in removing smut produced by the etching of a surface as well as in general cleaning.

1 . A composition comprising one or more fluoride ion compounds, one or more fluoride salts, one or more mineral acids, one or more organic acids, one or more surfactants and optionally one or more grain refiners.  
   
   
       2 . The composition of  claim 1 , wherein the fluoride ion compound is hydrofluoric acid, hydrofluorosilsilic acid, or fluoroboric acid or mixtures thereof.  
   
   
       3 . The composition of  claim 1 , wherein the fluoride ion compound is a fluoride salt.  
   
   
       4 . The composition of  claim 3 , wherein the fluoride salt is ammonium bifluoride or sodium fluoride or mixtures thereof  
   
   
       5 . The composition of  claim 1 , wherein the mineral acid is hydrofluoric acid, nitric acid, sulfuric acid, or phosphoric acid or mixtures thereof.  
   
   
       6 . The composition of  claim 1 , wherein the organic acid is oxalic acid or glycolic acid or mixtures thereof.  
   
   
       7 . The composition of  claim 1 , wherein the surfactant is nonionic surfactant, an amphoteric surfactant, or a synergistic surfactant.  
   
   
       8 . The composition of  claim 1 , wherein the surfactant comprises salts of alkyl aryl sulfonates, alkyl sulfonates, alkyl ether sulfates, alkyl sulfates, alkyl taurates, and alkyl sulfosuccinates.  
   
   
       9 . The composition of  claim 1 , wherein the surfactant comprises a hydrocarbon derivatives, abietic acid derivatives, ethoxylated primary alcohols, and modified polyethoxylated alcohols, individually or in combinations of two or more.  
   
   
       10 . The composition of  claim 1 , wherein the fluoride ion compound is present in an amount from about 10 to about 200 grams per liter.  
   
   
       11 . The composition of  claim 1 , wherein the mineral acid is present in an amount from about 40 to about 80 grams per liter.  
   
   
       12 . The composition of  claim 1 , wherein the organic acid is present in an amount from about 5 to about 20 grams per liter.  
   
   
       13 . The composition of  claim 1 , wherein the surfactant is present in an amount from about 1 to about 3 grams per liter.  
   
   
       14 . A composition for etching a metal, comprising ammonium bifluoride, hydrofluoric acid, glycolic acid, and surfactant.  
   
   
       15 . The composition of  claim 14 , wherein the surfactant is nonionic surfactant, an amphoteric surfactant, or a synergistic surfactant.  
   
   
       16 . The composition of  claim 14 , wherein the surfactant comprises salts of alkyl aryl sulfonates, alkyl sulfonates, alkyl ether sulfates, alkyl sulfates, alkyl taurates, and alkyl sulfosuccinates.  
   
   
       17 . The composition of  claim 14 , wherein the surfactant comprises a hydrocarbon derivatives, abietic acid derivatives, ethoxylated primary alcohols, and modified polyethoxylated alcohols, individually or in combinations of two or more.  
   
   
       18 . The composition of  claim 14 , wherein the ammonium bifluoride is present in an amount from about 10 to about 200 grams per liter.  
   
   
       19 . The composition of  claim 14 , wherein the hydroflouric acid is present in an amount from about 40 to about 80 grams per liter.  
   
   
       20 . The composition of  claim 14 , wherein the glycolic acid is present in an amount from about 5 to about 20 grams per liter.  
   
   
       21 . The composition of  claim 14 , wherein the surfactant is present in an amount from about 1 to about 3 grams per liter.  
   
   
       22 . The composition of  claim 14 , wherein the metal is aluminum or aluminum alloy.  
   
   
       23 . A method of treating the surface of a metal, which comprises contacting the metal with a composition comprising a one or more fluoride ion compounds, one or more fluoride salts, one or more mineral acids, one or more organic acids and one or more surfactants and optionally one or more grain refiners.  
   
   
       24 . The method of  claim 23 , wherein the treatment is done at a solution temperature of 70° F. to 150° F.  
   
   
       25 . The method of  claim 23 , wherein the treatment is done at a solution temperature of 100° F. to 120° F.  
   
   
       26 . The method of  claim 23 , wherein the fluoride ion compound is hydrofluoric acid, hydrofluorosilsilic acid, or fluoroboric acid or mixtures thereof.  
   
   
       27 . The method of  claim 23 , wherein the fluoride ion compound is a fluoride salt.  
   
   
       28 . The method of  claim 27 , wherein the fluoride salt is ammonium bifluoride or sodium fluoride or mixtures thereof  
   
   
       29 . The method of  claim 23 , wherein the mineral acid is hydrofluoric acid, nitric acid, sulfuric acid, or phosphoric acid or mixtures thereof.  
   
   
       30 . The method of  claim 23 , wherein the organic acid is oxalic acid or glycolic acid or mixtures thereof.  
   
   
       31 . The method of  claim 23 , wherein the surfactant is nonionic surfactant, an amphoteric surfactant, or a synergistic surfactant.  
   
   
       32 . The method of  claim 23 , wherein the surfactant comprises salts of alkyl aryl sulfonates, alkyl sulfonates, alkyl ether sulfates, alkyl sulfates, alkyl taurates, and alkyl sulfosuccinates.  
   
   
       33 . The method of  claim 23 , wherein the surfactant comprises a hydrocarbon derivatives, abietic acid derivatives, ethoxylated primary alcohols, and modified polyethoxylated alcohols, individually or in combinations of two or more.  
   
   
       34 . The method of  claim 23 , wherein the fluoride ion compound is present in an amount from about 2 to about 90 grams per liter.  
   
   
       35 . The method of  claim 23 , wherein the mineral acid is present in an amount from about 40 to about 80 grams per liter.  
   
   
       36 . The method of  claim 23 , wherein the organic acid is present in an amount from about 5 to about 20 grams per liter.  
   
   
       37 . The method of  claim 23 , wherein the surfactant is present in an amount from about 1 to about 3 grams per liter.  
   
   
       38 . The method of  claim 23 , wherein the treatment is done for about 5 minutes.  
   
   
       39 . The method of  claim 23 , wherein the metal is aluminum or aluminum alloy.