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Corrosion of Aluminum cold plate under Propylene Glycol - water solution [Wisconsin] 

September 23, 2009

Hi,
We are trying to use Aluminum cold plate, Alumiminum Heat exchanger, Steel pump, steel heater with inhibited propylene glycol water coolant.

What type of corrosion problems are likely to occur at cold plate or HeX that are made of Al. alloy?
How to study the corrosion rate?

Thanks,
Ashu

Ashu Joshi
- Waukesha, WI, USA

Just be aware that corrosion tables are set up by school boy engineers who weigh a piece of metal and immerse it in a pyrex beaker of solution for a period of time and then take it out and weigh it again. That will not work for you. With that combination of metals you mention there are all sorts of opportunities for various galvanic voltages to start corroding something.

Robert H Probert Robert H Probert Technical Services Garner, North Carolina Editor's note:        Mr. Probert is the    author of Aluminum How-To / Aluminio El Como

Hi,
Indeed, there is always a chance to overlook something or over simplify the corrosion analysis of a system but in your particular case, the combination of fluids and metals are the same present in most modern car cooling systems and they last for years. Propilene glycol is the main consituent of anti-freezers. Aluminum is the metal of choice for radiators and car water pumps are often steel. I would rather focus on other potential areas of problem, not this one.

Guillermo Marrufo
Monterrey, NL, Mexico