Galvanic corrosion between Aluminium and carbon fiber
Galvanic corrosion between Aluminium and carbon fiber
(OP)
Hi there,
I've been reading a bit in the forum and internet about the galvanic corrosion between aluminium.
We have a carbon fiber reinforced epoxy boxes with a load and they are hung in one end. We glue an aluminium insert. The gap is 150 microns around and the glue 3M DP 410.
In theory, there is no direct contact between the carbon fiber and the aluminium, since we have the glue everywhere around the aluminium.
We can't use glass fiber in between.
I am not familiarized with the treatments but there is a company here close by which can do a chromate (Alodine) the aluminium parts.
Do you think this is safe enough to avoid the galvanic corrosion?
thanks
regards
I've been reading a bit in the forum and internet about the galvanic corrosion between aluminium.
We have a carbon fiber reinforced epoxy boxes with a load and they are hung in one end. We glue an aluminium insert. The gap is 150 microns around and the glue 3M DP 410.
In theory, there is no direct contact between the carbon fiber and the aluminium, since we have the glue everywhere around the aluminium.
We can't use glass fiber in between.
I am not familiarized with the treatments but there is a company here close by which can do a chromate (Alodine) the aluminium parts.
Do you think this is safe enough to avoid the galvanic corrosion?
thanks
regards
RE: Galvanic corrosion between Aluminium and carbon fiber
This why modern airliners use Ti for the floor structure, so that they can use CF body and floor panels.
If this is glued to the side of a vertical surface, and if enough dirt and dust build up to bridge the glue joint, and if it gets damp, then the Al will be going away quickly.
I would look at coating the sides of the Al piece either with the glue or with a good coating (epoxy or urethane).
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P.E. Metallurgy, consulting work welcomed
RE: Galvanic corrosion between Aluminium and carbon fiber
RE: Galvanic corrosion between Aluminium and carbon fiber
It is very hard to suppress corrosion with that much driving voltage.
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P.E. Metallurgy, consulting work welcomed
RE: Galvanic corrosion between Aluminium and carbon fiber
Here some pictures (grey part: aluminium insert - brown part: carbon fiber box:
Knurling would be possible but the walls are very thin.
So anodizing would be better than chromating?
RE: Galvanic corrosion between Aluminium and carbon fiber
RE: Galvanic corrosion between Aluminium and carbon fiber
On aircraft interiors the drivers are cleaning agents and spilled soft drinks (cola is one heck of an electrolyte).
The worst non-seawater incidents that I have seen involved dust and dew. So think ahead.
If the face end of the box has been machined you may want to think about a thin plastic spacer there to prevent butting the Al directly against the raw CF edge with only glue as a separation.
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P.E. Metallurgy, consulting work welcomed
RE: Galvanic corrosion between Aluminium and carbon fiber
RE: Galvanic corrosion between Aluminium and carbon fiber
Good point 3DD, if the Al expands more it could split the end open, it is expands less then the bond line is gone.
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P.E. Metallurgy, consulting work welcomed
RE: Galvanic corrosion between Aluminium and carbon fiber