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Non corrosive metals for luminaires

Q. My company is going to purchase luminaires which will be installed in close proximity to coastal areas. Some luminaires which have been offered have their side entry sockets made of iron galvanized. The rest of the luminaires is made of Aluminum die-cast. How is, the iron part of the luminaires, going to affect their overall life given that the atmospheric conditions which prevail contain relatively large proportions of corrosive gases?

Antonios Gregoriou
eac, utility - Nicosia, Cyprus
2004

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Hi Antonios. As a metal finishing professional with some years of experience, but also a consumer who lives on a salt water lagoon, my conclusion is that a consumer -- even one with some years of experience in metal finishing -- usually cannot make worthwhile predictions about corrosion based on book knowledge of materials of construction, but must rely on the reputation of the manufacturer.

If the question you are posing were posed by a manufacturer of the luminaires, we would tell him that galvanizing some parts leads to dangers of galvanic incompatibility, and we might have a discussion of chromating the galvanized coating, and whether the galvanization layer is thick enough, etc., etc. But unfortunately that doesn't mean that the all-aluminum luminaires that you have been offered will prove better or worse from a corrosion standpoint :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004