Anodize/Hard Anodize/Alodine/Passivation

After passivation, corrosion resistance will be enhanced, chemical stability will be better, the appearance of color is not obvious, it is difficult to distinguish visually. Passivation normally applied on stainless steel, and anodize applied on aluminum. Sulphuric acid anodizing and passivation doesn’t impact the work piece’s dimension. Hard anodic oxidation will have a greater impact on the accuracy, generally dimension will increase 0.035-0.065mm per side.