Electroplating and galvanizing questions

Q. Dear Sir,

I am a student with a commerce background. My father has taken over a steel fabrication factory in the UAE, which also has a galvanizing plant. I am totally new to this field. Only recently did I come to know that electroplating and galvanizing are two different processes. I would like to know what are these two processes and what is their utility. Also what should be the ideal thickness of the coatings. Since these are very elementary questions you may choose not to answer them Therefore if you could even guide me as to what site I should look up or any book I should refer, I will really appreciate it.

A. Galvanizing is a process where parts are dipped into molten zinc. Zinc can alternatively be electroplated out of aqueous solutions (as can a couple dozen other metals). Economic zinc thicknesses for electroplating are well under .001". Economic galvanizing thicknesses are several times that.

For this reason, galvanizing is significantly more expensive but significantly more corrosion resistant than zinc electroplating. This question has been asked dozens of times over the years, so if you search the site you'll find additional detail. Good luck.

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

A. Dear Saba,

It's better to hire a consultant rather searching things your own because irrespective of thickness there are many other parameters also to be controlled to achieve good quality of galvanizing or zinc electroplating.

Best regards,

A. Electroplating is achieved by using an electrical current source (rectifier) to plate a metal on steel or other type of metal, and this is done for corrosion protection as well as cosmetic reasons (just like in wheels and car bumpers).

Where steel galvanizing is basically achieved by dipping the steel substrate into molten (melted) zinc, where the zinc becomes permanently part of the steel through a chemical process. This is done to protect the metal (steel) against corrosion and oxidation.

I hope I answered your question.