Mg with Al -> Problem?

[FSB1]

I read magnesium is soluble in aluminum
is it reasonable to have one part of aluminum in contact with one part made of magnesium?
Would I have degradation of the magnesium part? corrosion? ...

 

[EdStainless]

Depends on the environment, but high risk of Mg corrosion.
There are special coatings used on Mg because it corrodes in many situations.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[FSB1]

but any of these situations are in any way due to aluminum contact?

 

[gtaw]

Generally, when two different base metals are in contact (or close) with each other in the presence of an electrolyte, you can expect galvanic corrosion. The fact that one element is soluble in the other isn’t typically the cause of the corrosion.

Best regards - Al

 

[EdStainless]

The junction just makes it worse.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[GregLocock]

To use that combination you'd have to be 100% certain that no salt water is around.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[TugboatEng]

Honda used magnesium covers on their aluminum motorcycle engines. The magnesium water pump housing on my 1987 CR250 is mostly built out of Red Hand now. The external covers held up fine but even small amounts of water in the gearbox from the water pump leaks caused pitting on the insides of the mag covers.

 

[tbuelna]

http://www.autos.ca/auto-tech/auto-tech-bmws-30-litre-magnesiumaluminium-composite-engine-block/