November 19, 2017

Benefit of Anodized Aluminum

Any part that formed from aluminum metal should be anodized because the properties of origin aluminum metal will improved and change into better properties. Even of many anodized product can make more stand to corrode or stand to scratch but anodizing to aluminum is purposed to certain purpose of anodizing. The below lists are some reason why people doing anodizing to aluminum, outlined on the below:
  1. Anodizing aluminum is purposed to increase corrosion resistance. Oxide film that formed on the surface of aluminum sheet can stand to corrode in atmospheric condition and salt water attack. So this oxide film can protect underlying metal by serving as barrier from attracting some corrosive agent. To make the oxide film can protect the aluminum sheet is treated the aluminum sheet after anodized into hot water with slightly acidified, or use dichromate solution, or nickel acetate solution.
  2. Other reason to anodize aluminum improve decorative appearance. All anodic coating have lustrous and relatively good abrasion resistance. The degree of lustrous of anodic coating depends on the condition of aluminum before anodizing. Dull etching will decrease luster, bright etching, chemical or electrolytic brightening and buffing will increase luster either diffuse or spectacular. For this kind of aluminum finished are use in structural and architectural application.
  3. Aluminum anodizing can increase abrasive resistance. From the experience product result the thickness of hard anodizing about 25 micron (1mm) to more than 100 micron (4 mm). This thickness is enough for many applications that involving rotating parts where abrasion resistance is required.
  4. Some anodizing process is purposed to increase paint adhesion. Alloy metal from aluminum can anodized to activate the surface of alloy metal. Aluminum base alloy materials that are painted for service in severe corrosive environment are anodized before painting.
  5. Other reason of anodizing of aluminum alloy is improve adhesive bonding. This kind material are used in aircraft structure of most modern aircraft. Anodizing use phosphoric acid or chromic acid can improve bond strength and durability.
  6. Anodizing process also can improve lubricity, by combination of polishing or honing of hard anodizing to smoother surface before applying a polytetrafluoroethylene coating.
  7. General purpose of anodizing product is purpose for aesthetic performance, can provide unique, decorative finished color. As already discussed of mechanism of coloring in anodizing process, that sealing of anodizing aluminum is together with coloring of oxide film on the surface of aluminum. Integral anodizing, depending on the alloy composition, is used to provide a range of stable earth-tone colors suitable for architectural applications.
  8. Anodizing process also purpose to provide electrical insulation. Aluminum oxide is a dielectric, that mean can’t conduct electric current until certain voltage. The breakdown voltage of anodic film varies from a few volts to several thousand volts. This depend on the alloy properties itself and on the natural and thickness of oxide film on the surface.
  9. Anodizing of metal also make subsequent plating. The porosity of certain anodic films enhances electroplating.
  10. Anodized surface of aluminum can detect of surface flaws. Chromic acid solution bath can be used as an inspection medium for detection of fine surface cracks. When object containing surface flaws is removed from anodizing bath, then washed and dried quickly, chromic acid entrapped in the flaws seeps out and stains in the anodized coating in around of the flaws.

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