Question regarding metal alloys used in aircraft..

[beaucaire]

On a.net some posts cover a potential (conditionel !)change in design for the Boeing 787 due to incompatibility of certain materials.

I understand that the mix of certain metal-alloys in conjunction with carbon-fibre or graphite –fibre can result in substantial generation of electricity. (That’s why many dentists take out older mercury-alloys teeth fillings and replace them with ceramic fillings...)
Aluminium being a less-noble metal than titanium seems to be subject to more corrosion-related electron-generation.
I would be interested to learn why this alloy-related “battery” effect was not earlier considered by both manufacturers ( one mentioned that Airbus had to use titan rather than steel or aluminium for the pods in order to counter this effect.)

[cwatters]

> I would be interested to learn why this alloy-related
> “battery” effect was not earlier considered

What makes you think it wasn't considered at the right time? It's been a know issue for at least 10 years.

Google will find you some articles..

Aircraft Corrosion Design Issues
http://www.corrosion-doctors.org/Design/aircraft-design.htm

Design for Corrosion
http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.htm

> many dentists take out older mercury-alloys
> teeth fillings and replace them with ceramic fillings.

Nope. Some dentists do remove fillings but not because there is an electrolytic action - its usually because the patient has become scared of the mercury. Try asking about this at sci.med.dentistry and see what answers you get.

[beaucaire]

Thanks for the link- I learned something !