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Is dry galvanic corrosion possible?

Is galvanic corrosion possible in this situation. A galvanized bolt securing a chrome plated plate to an chrome plated aluminum housing in a dry environment. The situation in new assembled parts with "white powdery corrosion" on the heads of assembled parts. Everything I have read necessitates a liquid. Thank you for your help. We really must solve this problem.

Randy Wallis
1st tier automotive - Seattle, Washington, USA
2003

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In theory ionic reactions can take place in a solid solution, but I am not aware of any corrosion systems that occur in this type of environment, so the answer to your question is a "no". The conventional understanding of corrosion is the formation of metal salts and/or oxides and/or hydroxides from the basic metal. The corrosion process carries on by the reaction of ions and ions need a suitable solvent, such as water. I do not understand what you mean by "The situation in new assembled parts with "white powdery corrosion" on the heads of assembled parts". Do you mean the galvanised bolt has a white deposit on the top of its head, or is the powdery deposit on the aluminium? I would expect to find that the assembled parts have been exposed to a wet environment or have had some sort of chemical drip onto them and the liquid has evaporated to leave the white deposit. However, it would be a good idea if we could have a picture of the problem and perhaps an analysis of the corrosion products

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2003