Key Benefits of Type III Anodizing:
• High hardness (up to 70 Rockwell C) for extreme wear resistance
• Excellent corrosion resistance in aggressive environments
• Thick coatings up to 0.004” for added protection
• Dielectric properties for electrical insulation
• Can be left natural (dark gray/black) or dyed for identification

HARDANODIZING PROCESS
Type III anodizing is performed in a concentrated sulfuric acid bath at a low temperature (typically 0–3°C) and with a high current density.The process forms a thick, dense oxide layer that is much harder and more wear-resistant than standard anodizing.
1. Cleaning and Preparation
Parts are thoroughly cleaned and deoxidized to remove contaminants and ensure uniform oxide growth. Surface finishes may be etched or brightened depending on application needs.
2. Anodizing
A high current is applied to create the dense oxide layer.The exact voltage and amperage are controlled based on alloy type and target thickness.
3. Coloring (Optional)
Due to the density of the oxide, Type III coatings are naturally dark gray or black. They can be dyed darker or color-coded using special techniques if needed.
4. Sealing
Sealing in hot water or nickel acetate is optional, depending on the desired corrosion resistance and dye retention.