carbon fiber causing steel corrosion

[wash u fsae]

I've researched bonding carbon fiber to steel and I seem to have found quite a few studies linking corrosion to direct carbon fiber contact with steel. Has anyone had any experience with this? Have any teams bonded carbon fiber to steel?

[vinHonda]

Upon close inspection of our 2002 and 2003 cars..... no corrosion. Although, the carbon only is a small line touching the steel, most of what is bonded/touching the steel is the nomex core.

Vinh

[-]

If you do some more reaserch you will find that eliminating the corrosion problems between composites and metals is a large problem. It is something that the aerospace and the military have spent a large amount of time and $$$ on. Also what enviorment did the research say the parts were in. From what I remember the enviorment played a large role also.

just food for thought.

[leclercjs]

On this, I've done a research because we may be thinking doing an half and half steel/carbon fiber frame and many people told me that anodizing your frame would help slow down the effect of corrosion.

Just a hint, not the answer to the problem.

But Vihn, on you pictures of this year's car, is the frame anodize or it is the frame painted in green?

[Didier Beaudoin]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by leclercjs:
On this, I've done a research because we may be thinking doing an half and half steel/carbon fiber frame and many people told me that anodizing your frame would help slow down the effect of corrosion.

Just a hint, not the answer to the problem.

But Vihn, on you pictures of this year's car, is the frame anodize or it is the frame painted in green? <HR></BLOCKQUOTE>

How can you anodize steel? AFAIK, anodizing is for aluminium only...

On my point of view a primer plus a good coat of paint does the trick, as much as a cadmium plating like we see on bolts and nuts.

[Brent Howard]

Dider,

I was going to post the same thing about anodizing, but normally when I say something like that someone proves me wrong . However, anodizing is only for aluminum.

I was wondering about the painting comment though. Although I think this corrosion must be simaler to galvanic corrosion and so any seperation of the steel and carbon, or carbon resin (??) would be good I'm not so sure paint would be a good idea. The reason I say this is that now you are bonding to the paint and relying on that steel paint and paint-carbon resin bond to hold your parts together. Also, remember that you need water (or another electrolyte) to have any corrosion, so just keep the car dry normally and don't let it sit out in the rain and it will be fine.

Brent

[dancin stu]

At work last year, we were bonding carbon floorpans to steel chassis. The chassis were shot blasted and epoxy powder coated before bonding. We abraided the powder coat with a very course grit, being careful not to go through to the steel, before using two part epoxy resin to glue them together. The bond was incredibly strong, one chassis survived some extreme abuse courtesy of torsional testing, and nos igns of corrosion were evident. Im guessing if comprehensive lab work were carried out, the powder coat would fail before the glue, although the powder coat is very very durable, and almost impossible to remove, certainly not with a file.

Don't know how feasible powder caoting would be for a Formula Student car, I believe it is quite expensive, but the finish is excellent.

[Brent Howard]

Powdercoat definitly bonds stronger than regular paint. It is fairly cheap too for an FSAE chassis. We had our 2002 chassis powdercoated and it cost around $350 I think. The weight added however was rather high, 5lbs over the same chassis painted.

Brent

[dancin stu]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>The weight added however was rather high, 5lbs over the same chassis painted.

Brent <HR></BLOCKQUOTE>

Thats the thing, think the judges might pick upon it, these chassis are not used every day, and owners will probably keep them away from moisture, although you can forget about chassis maintenance if it is done

[Didier Beaudoin]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Brent Howard:
Dider,

I was going to post the same thing about anodizing, but normally when I say something like that someone proves me wrong . However, anodizing is only for aluminum.

I was wondering about the painting comment though. Although I think this corrosion must be simaler to galvanic corrosion and so any seperation of the steel and carbon, or carbon resin (??) would be good I'm not so sure paint would be a good idea. The reason I say this is that now you are bonding to the paint and relying on that steel paint and paint-carbon resin bond to hold your parts together. Also, remember that you need water (or another electrolyte) to have any corrosion, so just keep the car dry normally and don't let it sit out in the rain and it will be fine.

Brent <HR></BLOCKQUOTE>

Brent,

I'm not sure about galvanic corrosion needing an electrolyte to happen. After all, the materials are exchanging electrons directly from one to another since they are in contact...