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Gold or Other Metal Plating on Aluminum for Chemical Resistance to Mild Aqueous Conditions

I am looking for advice on a coating for scientific equipment that will be machined from aluminum. The machined part will have wells that will contain aqueous solutions of proteins, buffers (4<pH<11), salts. While for the most part innocuous, I want to avoid direct contact with Aluminum surface and thought gold would be the best plating. Added advantage of gold is that the entire device will be immersed in a water bath to maintain a very constant (± 0.005 C at 20 C) temperature, and gold is an excellent heat conductor. However, I am finding that gold is somewhat porous and have no idea if this will have an effect on the experiments. How difficult is it to plate small pieces of aluminum (13" x 3" X 1/2") with gold (can it be done well with electroplating "kits"?) and are there good alternatives to gold that are chemically resistant and non-porous?

The purpose of the inquiry is to see if I can make an isopiestic apparatus from a single bar of metal; isopiestic devices date back to 1918 when Bousefield introduced the idea of balancing the vapor pressure of water over different aqueous solutions.

George DeTitta
scientist - Buffalo, NY
February 2, 2010

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Hi, George. Gold plating might be ideal. Find a plating shop that does gold plating and has experience in electroplating of aluminum, and I'm sure they can do exactly what you need. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 2, 2010