Fretting corrosion in electrical connectors
Typ
Examensarbete för masterexamen
Program
Publicerad
2020
Författare
Nord, Vilma
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This thesis studies how fretting corrosion on electrical connector terminals are influenced
by fretting as well as evaluating different analysis methods for studying fretting in industry
produced electrical connectors. Fretting is a mechanism of degradation that influences surfaces
meant to be stationary in regards to each other but due to for example vibrations a small
relative movement exists. It is today largely unknown how temperature influence fretting and
the methods currently used by Volvo cars to study this phenomenon in electrical connectors is
mostly limited to optical microscopy.
A vibration rig was used to study the fretting phenomena. But before fretting tests could
be done a fixture needed to be made and vibrations levels measured and analysed. Fretting
tests where performed for 24h at 100 m/s2 peak amplitude while sweeping from 100-2000
Hz. These tests where done at 8 different temperatures from -40 ◦C to 100 ◦C. Samples were
thereafter analysed using optical, scanning electron and light interference microscopy.
It was found that temperature affected fretting in three ways. Firstly higher temperature
resulted in higher amplitude relative motion between the terminals and larger fretting scar.
Secondly temperature was found to influence the surface structure of the fretting scar. For
colder temperatures more abrasive deformation was found where as for higher temperature
there were more adhesive deformation. Lastly it was found that the plating thickness degraded
faster at higher temperature. On another note SEM microscopy was found to be very useful
when analysing fretting and provided many insights which would have been hard to achieve
with only optical microscopy. The light interference microscopy however was not found useful
in this thesis but this was more likely due to the instrument and not the method.