Non-chromated aluminum desmutting compositions

Claim 1

ACIDIC AQUEOUS SOLUTION FOR DESMUTTING ALUMINUM AND ALUMINUM ALLOYS CONSISTING ESSENTIALLY OF WATER AND HYDROGEN, FERRIC AND FLUORIDE IONS, IN WHICH THE HYDROGEN ION CONCENTRATION LIES WITHIN THE RANGE OF 0.18 TO 1.4 GRAMS PER LITER, IN WHICH THE FERRIC ION CONCENTRATION LIES WITHIN THE RANGE OF 2 TO 17 GRAMS PER LITER, IN WHICH THE FLUORIDE ION CONCENTRATION LIES WITHIN THE RANGE OF 0.4 TO 3.3 GRAMS PER LITER, IN WHICH SOLUTION THE RATIO OF THE HYDROGEN ION CONCENTRATION TO THE FERRIC ION CONCENTRATION LIES WITHIN THE RANGE OF 0.03 AND 0.36 AND IN WHICH SOLUTION THE RATIO OF THE FLUORIDE ION CONCENTRATION TO FERRIC ION CONCENTRATION DOES NOT EXCEED THE VALUES GIVEN BY CURVE AB OF THE DRAWING FOR THE CORRESPONDING RATIOS OF HYDROGEN ION CONCENTRATION TO FERRIC ION CONCENTRATION, THE SAID SOLUTION ALSO BEING SUBSTANTIALLY FREE OF CHLORIDE ION, SAID HYDROGEN ION BEING PROVIDED BY AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID, HYDROFLUORIC ACID, SULFAMIC ACID, NITRIC ACID, ALKALI METAL ACID SULFATE, AND AMMONIUM ACID SOLFATE, SAID FERRIC ION BEING PROVIDED BY AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF FERRIC SULFATE, FERRIC FLUORIDE, FERRIC FORMATE, FERRIC NITRATE AND FERRIC FLUOSILICATE, SAID FLUORIDE ION BEING PROVIDED BY AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF FERRIC FLUORIDE, FERRIC FLUOSILICATE, ALKALI METAL FLUORIDE, ALKALI METAL FLUOSILICATE, ALKALI METAL FLUOBORATES, ALUMINUM FLUORIDE, AMMONIUM FLUORIDE, ALKALI METAL ACID FLUORIDES, AMMONIUM AICD FLUORIDE AND HYDROFLUORIC ACID.