HARD ANODIZING, TYPE III

Hard anodized coatings on aluminum and aluminum alloy products are formed in the electrolytic oxidation process in acidic electrolytes in specially selected temperature and current conditions. One half of the coating’s thickness penetrates the base material and the other half forms a layer on the outside of the material. Compared to conventional anodized coatings on aluminum, hard-anodized coatings are thicker and have much higher abrasion resistance. Depending on the type and condition of the base material, the thickness of the hard-anodized coating can be in the range of 25-250 ľm.

The color of hard-anodized coatings depends on the type of the based material and on the coatings’ thickness. Typical colors are various shades of brown and gray. In the case of very thick coatings, the color can be black.

PROPERTIES OF HARD-ANODIZED COATINGS

• Very high abrasion resistance
• Excellent corrosion resistance
  (1,000-1,500 hours in a salt chamber)
• Very high hardness (380-550 HV 0.025)
• Optimum antifriction properties
• High puncture resistance
  (1,500 V at 50 ľm thickness)
• High heat resistance
  (up to 2,000 oC for short exposure)
• Excellent thermal insulation properties
  (1/10 to 1/30 of the thermal
  conduction of the base material)

TYPICAL APPLICATIONS FOR HARD-ANODIZED COATINGS

1. Pneumatic and hydraulic cylinders
2. Pistons
3. Injection molds
4. Valves
5. Nozzles
6. Belt wheels
7. Surgical instruments
8. Gear transmissions
9. Heating panels
10. Kitchen utensils (pans, pots, etc.)
11. Automotive industry
12. Airspace industry

INFORMATION FOR CUSTOMERS

The purchase order for the hard anodizing service must contain the following information:

1. The alloy the elements are made from
2. The alloy’s hardness
3. The thickness of the coating
4. Indication of the location of electric contact
5. The technical drawing of the elements (if possible)

NOTE: If the information on the alloy and its condition is incorrect, the elements may become damaged.