Galvanizing of Die Cast Aluminum

[matt425]

We use small die cast AL380 parts that are plated. We would like to get a galvanized appearance for some of these parts. Is it possible to galvanize aluminum? Is there another coating anyone can recommend to get this appearance? It is an outdoor application, but the conditions are not overly harsh.

Thanks,
Matt

 

[Goahead]

Zincating is a procedure of immersion plating employed for coating aluminum surfaces with zinc prior to electroplating. Various metals, including zinc, can be electroplated on zincated surfaces.

http://www.welding-advisers.com/

 

[swall]

By "galvanized appearance" do you mean the spangled appearance of hot dip galvanize or the uniform silver color typically seen with electro galvanize?

 

[matt425]

The spangled appearance is what we are looking for. The parts currently are plated to get a uniform silver or gold color.

 

[swall]

I have seen this sort of spangled appearance on aluminum die castings that were vibratory cleaned in a ceramic media, similar to what would be used for deburring. This is what I would try. Then for corrosion resistance, you could apply a clear chromate (or chrome free) conversion coating.

 

[ehw]

may be they can help you

http://www.roslerusa.com

(I agree with swall - vibratory cleaning may help) - otherwhise painting

 

[btrueblood]

Would a light etch after vibratory cleaning/polishing bring out the grain structure of the die casting? I have no idea what would give a "light etch" on die cast Al though.

 

[swall]

No. The grain size (dendrite size, actually) in a die casting is so small that it would not be apparent on a macro scale.ehw raises a good point about painting, especialy if powder coating is considered. There are lots of metallic finsishes available with powder coat that can give a metal flake appearance, a hammer finish, etc.