Low-cost superhydrophobic surface treatment method of aluminum alloy

The invention provides a low-cost superhydrophobic surface treatment method of aluminum alloy, which comprises the following steps: (1) carrying out chemical etching on the surface of the aluminum alloy by utilizing hydrochloric acid aqueous solution with the mass-volume concentration of 70g/L-95g/L in water bath at the temperature of 30-50 DEG C for 3-6min; and (2) carrying out evaporation modification on the surface of the aluminum alloy by utilizing long chain fatty acid solution by an evaporation method, wherein, the long chain fatty acid comprises at least one of lauric acid and stearic acid, and the long chain fatty acid solution is prepared by dissolving fatty acid into an ethanol solvent based on the mass percent of 3wt.%-15wt.%. The evaporation method comprises the following steps: placing the long chain fatty acid solution and the aluminum alloy subject to chemical etching treatment in a sealed container; putting the sealed container in a chamber electric furnace, heating until the temperature of th