Hard anodization was a method that can enhance aluminium alloy surface characteristics by growing an aluminum anodic oxide (AAO) film on it surface. This method was very applicable to obtain a thick and hard coating. This process was carried out at galvanostatic-potentiostatic mode at high current densities (j = 4.2 A/dm2), high target voltages (Vt = 30-60 V) and low electrolyte temperature. Two sulfuric acid electrolyte was compared, the first solution was sulfuric acid 11% vol., the second one was sulfuric acid 11% vol. plus oxalic acid 1% wt, both of them was conditioned at <5°C. The maximum AAO film thickness and hardness obtained was 110.01 µm and 400 HV. The increasment of target voltage was directly proportional to the increase in thickness and hardness of the AAO film. The results of this study could be synergized with the manufacturing process of aluminum alloy-based (Al6061) components at the product finishing stage. The logarithmic regression in the function of target voltage could be used to estimate film thickness and hardness of the films.