Help to visually identify a corrosion type

[Molydood]

Hi all,

I work in the "product assurance" department for an automotive company, and we have encountered what looks to be a corrosion effect during a controlled test (85 degrees C and 85% relative humidity) on one of our components.

I feel that my limited knowledge of chemistry is really letting me down with this one (most of our failure mechanisms are mechanical or electrical)... I wonder if anybody can identify visually or with an intelligent guess, at the type of corrsosion this is (see attached picture?)

We have checked the humidity chamber and the water has been de-ionised and has a resistance of 60kohms/cm. It appears that both the large metal bracket and also the small metal screw have been effected, so we are suspecting a test setup issue (ie some contaminent is entering the chamber maybe diffusing off the surface of the bracket)

any help would be appreciated

Martin

 

[PhaseShifter]

Is the bracket made out of zinc or aluminum?
Is the screw made of steel?

 

[Molydood]

bracket is steel
screw - not sure, will go and check, but its probably plated