Abstract: The process which is the object of the invention concerns the surface treatment of aluminum alloys by anodization. It consists of treating the aluminum alloy objects to be coated by making them the anode in a bath through which a direct current passes, under the following operating conditions:-- chromic acid bath of a concentration of 100 to 200 g/liter- temperature of 55.degree. to 70.degree. C-- current density of 3.5 to 5 amperes/dm.sup.2-- cathode surface area less than 0.06 times the volume, in liters, of the bath-- anode surface of 1.7 to 2.3 times the volume, in liters, of the bath. Under these conditions a high oxide layer growth rate is obtained, namely 1 micron per minute. The process can be used in particular in the anodization of continuous strips.