Carbon Steel vs Aluminum (Corrosion)

[bkervaski]

Good Morning VAF!

I'm trying to figure out how Carbon Steel and Aluminum will get along where priming the (non-structural) parts is not practical.

While researching, I'm learning a lot how various materials can cause corrosion, but I'm finding conflicting information.

I found the chart below, am I to assume that Carbon Steel and Aluminum are just fine together?

 

[Freemasm]

The reason that you get conflicting info is probably perspective when viewing some of the charts. With rare exception (mostly noble metals) , dissimilar metals will exchange electrons. This is especially true when a catalyst is introduced (water and more specifically the stuff in water). It could be evident in days or decades; so,

it comes down to practicality and the intended service life. Your application should be fine. If you can't prime the faying surfaces, then keep the catalyst away by applying a preservative oil.

Ref post 4 here if you'd like:

https://vansairforce.net/threads/which-corrosion-inhibitor.197941/

 

[RVDan]

Then there is the fact that aviation hardware is plated with cadmium which is next to aluminum on the chart.

 

[Carl Froehlich]

it comes down to practicality and the intended service life. Your application should be fine. If you can't prime the faying surfaces, then keep the catalyst away by applying a preservative oil.

Exactly. The rule for RVs is anytime two pieces of metal come together (any metal), apply grease if you ever want to take them apart. Examples include gear legs into weldments.

Carl