Summary for carbon fiber corrosion on metal Discussion
carbon fiber corrosion on metal is discussed in terms of whether a kevlar/graphite weave over steel or aluminum car panels will cause galvanic attack. Alexander Duncan asks if sanding, alcohol cleaning, 3M spray adhesive, epoxy, and clear coat will isolate the metal enough to prevent corrosion. Guillermo Marrufo says that if there is no liquid or gaseous path for metal ions to travel, there should be little or no galvanic action; if the process uses a liquid that later crosslinks or freezes, any attack should stop soon and the composite can be relied on. A second answer agrees, saying problems with metals and composites are mainly long-term and involve constant exposure to acid fumes. He notes permeation is more of an issue in some composites than thermoplastics, but concludes the paneling should not be affected.
Q. I am into the current craze with carbon fiber paneling. I work on aircraft and deal with structural maintenance and corrosion. I remember learning about graphite paneling and it’s severe corrosion potential on unprotected metal. I am looking to cover steel car paneling and Al auto parts with a kevlar/graphite weave for cosmetic appearance. I wonder what kind of problems are foreseen? I intend to sand and clean the panel with 180 grit and final clean with alcohol. After this lay the fabric with 3M spray adhesive
⇦ on
or
Amazon [affil link] and epoxy/ clear coat over the top. I wonder if the 3M adhesive is enough of a separation to prevent corrosion on metal parts or if something else is needed.
Thanks for your help,
Alexander Duncan
USAF – Dover, Delaware, USA
2003
A. As long as there is no liquid or gaseous via for the metal ions to travel, there should be no or almost no galvanic action. If the procedure intrinsically involves some kind of liquid but eventually freezes (crosslinking) then the possible attack will stop soon and you can rely on the composite.
Guillermo Marrufo
Monterrey, NL, Mexico
A. Hi Alex,
I think that Guillermo’s reply hits the nail on the head.
The only time you’d encounter ‘problems’ with metallics and composites would be a) longish term b) constant travel of acid fumes.
The reason for this is that the permeation of glass fibre epoxy or thermoset composites, silicon carbon fibres is more pronounced than with thermoplastics. I can only recall one instance (Stelco Steel, Hamilton, Ontario) where the embedded metal reinforcing failed due to permeation in an exhaust system.
Worry not. Thy panelling will not be affected.
Freeman Newton [deceased]
R.I.P. old friend (It is our sad duty to
advise that Freeman passed away 4/21/12)