On the anodized aluminum there are a problem when aluminum is going bad on the surface and this need to remove the oxide scaling on the surface. It is essential that metal to be plated be free of scale and oxide for quality plating. Good shop practice can prevent or minimize scale problems. Such things as cleaning before heat treating, wearing gloves to keep fingerprints off metal surfaces, proper control of heat treat furnaces, and taking step to prevent rusting of steel parts pay for themselves. It is literally true that "an ounce of (scaling) prevention is worth a pound of cure."
And find more about modern electroplating technology and type of metallic coating like chrome plating, bright chrome plating, dull black chrome plating, white chrome plating, gold color chrome plating, silver plating, gold plating, copper plating, anodizing, aluminum anodizing, black anodized, red anodized, yellow anodized, bronze color anodized, silver anodized, gold anodized, zinc coating, galvanizing.
And find more about modern electroplating technology and type of metallic coating like chrome plating, bright chrome plating, dull black chrome plating, white chrome plating, gold color chrome plating, silver plating, gold plating, copper plating, anodizing, aluminum anodizing, black anodized, red anodized, yellow anodized, bronze color anodized, silver anodized, gold anodized, zinc coating, galvanizing.