Hard-head anodized internal combustion engine piston and manufacturing method thereof

The invention relates to a hard-head anodized internal combustion engine piston. The substrate thereof is made of Al-Si alloy. The invention is characterized in that the external surface of the piston head has an anode oxide film with the thickness of 8-60 mu m. A anode oxide film generation technique adopts DC power supply anodization, and comprises the following steps: chemical-deoiling, washing with hot water, washing with cold water, polishing, washing with cold water, oxidizing and washing with cold water. The technological conditions of anodization are as follows: the voltage is 45-70 V, the oxidizing current density is 3-7 A/dm , the temperature of oxidizing solution is -5-0 DEG C, and the oxidizing time is 30-60 minutes; and in the oxidizing solution, the concentration of sulfuric acid is 200-240 g/L, the concentration of oxalic acid is 15-20 g/L, and the concentration of aluminum sulfate is 0.2-0.5 g/L. The technological method is easy to master and can easily realize automatic control on parameters.