Abstract: An aqueous composition for the electrolytic deposition of a chromium coating on the surface of a substrate is disclosed, in which it has a pH of between 0 and 1 and which contains a trivalent chromium salt, glycine, an alkali metal salt, an aluminium salt and, optionally, an ammonium salt. The chromium plating process according to the invention comprises the immersion of the substrate to be treated in this composition and the application of a current between this substrate and an anode. This process makes it possible to form a high-quality chromium coating on the entire surface of the substrate.

Abstract: A method for anodizing a part made of aluminum or an aluminum alloy by immersing the part in an aqueous bath essentially comprising sulfuric acid at a concentration of 150 to 250 g/L and at a temperature of 5 to 25° C. A DC voltage according to a voltage profile comprising a voltage increased at a rate of 1 to 32 V/min is applied to the part. The voltage is maintained at a plateau voltage value of 12 to 20 V for a duration sufficient for obtaining, at the surface of the part, an anode layer having a thickness of 3 to 7 ?m and/or a layer weight of 20 to 150 mg/dm2.

Abstract: A method for surface treatment of a part made of aluminum, magnesium, or one of the alloys thereof, to protect the part from corrosion. The method comprises consecutively immersing the part in a first aqueous bath containing a corrosion-inhibiting metal salt and an oxidizing compound, and a second aqueous bath containing an oxidizing compound and a corrosion-inhibiting rare-earth salt. The method can be carried out for the chemical conversion of aluminum or the alloys thereof, and of magnesium or the alloys thereof, on parts that have not been previously treated, or after anodizing the part to seal the anodic layer.

Abstract: A method for anodizing a part made of aluminum or an aluminum alloy by immersing the part in an aqueous bath essentially comprising sulfuric acid at a concentration of 150 to 250 g/L and at a temperature of 5 to 25° C. A DC voltage according to a voltage profile comprising a voltage increased at a rate of 1 to 32 V/min is applied to the part. The voltage is maintained at a plateau voltage value of 12 to 20 V for a duration sufficient for obtaining, at the surface of the part, an anode layer having a thickness of 3 to 7 ?m and/or a layer weight of 20 to 150 mg/dm2.

Abstract: A method for surface treatment of a part made of aluminum, magnesium, or one of the alloys thereof, to protect the part from corrosion. The method comprises consecutively immersing the part in a first aqueous bath containing a corrosion-inhibiting metal salt and an oxidizing compound, and a second aqueous bath containing an oxidizing compound and a corrosion-inhibiting rare-earth salt. The method can be carried out for the chemical conversion of aluminum or the alloys thereof, and of magnesium or the alloys thereof, on parts that have not been previously treated, or after anodizing the part to seal the anodic layer.

Abstract: An anticorrosion treatment process in which applied to an oxidizable surface of a solid metal substrate is a liquid solution, referred to as treatment solution, including: at least one alkoxysilane, and at least one cerium (Ce) cation; in a liquid aqueous-alcoholic composition, the treatment solution being suitable for being able to form, at the surface of the solid metal substrate, a hybrid matrix by hydrolysis/condensation of each alkoxysilane(s) and of each cerium (Ce) cation; the treatment solution having a molar ratio (Si/Ce) of silicon element of the alkoxysilane(s) with respect to the cerium (Ce) cation(s) of between 50 and 500; characterized in that the cerium (Ce) cation(s) has(have) a concentration between 0.005 mol/L and 0.015 mol/L in the treatment solution.