Galvanic Corrosion in Carbon Fiber Materials

Just a few weeks ago, the topic of galvanic corrosion was discussed at length on this blog. One aspect of galvanic corrosion that was not mentioned in that post was how the use of carbon fiber materials would affect preventative measures against corrosion.

Why Carbon Fiber?

Carbon fiber is attractive to engineers and manufacturers because it possesses a high specific strength. The specific strength is the ratio of a material’s yield strength to its mass density.

Manufacturers find carbon fiber materials ideal for their applications because of their low crack growth, lighter weight and general cost effectiveness in mass production. The most popular use of carbon fiber is within the aerospace and automobile industries.

The Problem with Carbon Fiber

The issue with using carbon fiber materials for fastener applications is that carbon fiber is electrically conductive, thus making it more susceptible to galvanic corrosion. When coupled with a fastener, bolt or nut, the situation worsens. Aluminum and plain steel, when coupled with a carbon composite, are both highly susceptible to galvanic corrosion.
Galvanic corrosion with carbon fiber materials has been an issue for decades, but experts have yet to produce a universal solution for the problem.

Your Best Solutions

Extensive testing has shown that coupling the carbon composite with titanium and its alloys – rather than aluminum or plain steel – is your best chance of limiting galvanic corrosion. Stainless steel is also less susceptible to galvanic corrosion when coupled with carbon fiber materials, but that also runs the risk of suffering pitting or crevice corrosion.

As the use of carbon fiber materials becomes more prevalent in fastener applications with products from bigHead® and BCT®*, understanding the role it plays in galvanic corrosion going forward has become even more important. To learn more about galvanic corrosion in fastener applications with carbon fiber materials, contact Bossard at ProvenProductivity@bossard.com.