When an anodized surface coating is damaged in service, it can be partially restored by

When an anodized surface coating is damaged in service, it can be partially restored by

• A. Applying a thin coat of zinc chromate primer
• B. Chemical surface treatment
• C. Use of a suitable mild cleaner
• D. Re-anodizing the entire part

Answer: (B)

Anodized aluminum gets its protection from a thin oxide layer. When that coating is damaged, you don’t want to just paint over it or rely on cleaning alone; you need to restore the protective barrier on the exposed area. A chemical surface treatment does this by removing the damaged oxide and applying a conversion coating (a chromate-type coating) to the exposed metal. This chemically bonds to the surface and re-establishes corrosion resistance and paint adhesion, and it can be applied only to the damaged spot, leaving the rest of the part as is. Re-anodizing the entire part is unnecessary for small areas and more involved, while a thin primer or a mild cleaner won’t restore the protective oxide, and would not provide the same durable, integrative protection.

Anodized aluminum gets its protection from a thin oxide layer. When that coating is damaged, you don’t want to just paint over it or rely on cleaning alone; you need to restore the protective barrier on the exposed area. A chemical surface treatment does this by removing the damaged oxide and applying a conversion coating (a chromate-type coating) to the exposed metal. This chemically bonds to the surface and re-establishes corrosion resistance and paint adhesion, and it can be applied only to the damaged spot, leaving the rest of the part as is. Re-anodizing the entire part is unnecessary for small areas and more involved, while a thin primer or a mild cleaner won’t restore the protective oxide, and would not provide the same durable, integrative protection.