surface preparation / bonding composites

Hi , im trying to find out what sort of surface preparation i would require to succesfully bond titanium to carbon fibre ??? Any thoughts appreciated

What adhesive are you using?

Ti has an oxide layer that is stable so with any luck you can bond to that directly, rather than trying to bond to the metal. So, rough it up with wet and dry to maximise the surface area, degrease with MEK, and good luck. If you are bonding finished CF parts to the Ti you need to surface prep them as well, clean the goop off with MEK, scratch with coarse emery, and PERHAPS hit it with a clean flame to activate the surface (don't do this unless you can afford to experiment, but its a good way of bonding to the more recalcitrant plastics).

I suggest you follow exactly the advice of the adhesive manufacturer!
Surface prep will vary e.g. epoxy may require a surface etch or bead blast of the Ti and a silane primer, whereas a structural acrylic will require a different primer and no etch.

High speed termal spraying does the job too.

Possibly a bit costly....

Edited by MatsNorway, 02 February 2012 - 16:53.

What adhesive are you using?

Ti has an oxide layer that is stable so with any luck you can bond to that directly, rather than trying to bond to the metal. So, rough it up with wet and dry to maximise the surface area, degrease with MEK, and good luck. If you are bonding finished CF parts to the Ti you need to surface prep them as well, clean the goop off with MEK, scratch with coarse emery, and PERHAPS hit it with a clean flame to activate the surface (don't do this unless you can afford to experiment, but its a good way of bonding to the more recalcitrant plastics).

Hi Im using 3m's structural adhesive 9323 .Ive previously been told to only lightly abrade ( max 120 grade ) the carbon as not to damage the fibres ? Cant sem to find how to prepare the titanium ? Thanks for all the advice so far

Hi Im using 3m's structural adhesive 9323 .Ive previously been told to only lightly abrade ( max 120 grade ) the carbon as not to damage the fibres ? Cant sem to find how to prepare the titanium ? Thanks for all the advice so far

5portsrock,

Titanium bonds well to carbon composites due to its galvanic compatibility and reasonable CTE match. However, ti and carbon don't have similar MoE properties. So it would be a good idea to design your ti part so that it has a thin, tapered, flexible edge where the bondline terminates. This will minimize the tendency of the ti/carbon bond to peel.

Good luck.
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Ti to CFRP are very commonly joined in bicycle frames. Might be worth a look.

Thanks to all, for the replies