Evaluation of the X-Ray CT Visualisation Technique for Characterising Electrical Contacts

The visualisation of two contacting surfaces has typically involved profiling each surface when separated. These profiling techniques have included scanning probe microscopy to a resolution down to the nanometre scale and optical non-contact profiling techniques at the sub-micrometre scale. Moreover, a number of techniques are being developed to profile the contacting surfaces in situ, i.e. without the need to separate the surfaces. An X-Ray Computer Tomography (CT) technique is under development at Southampton to visualise electrical contacts without dismantling the component parts. Contact maps of high force bolted interfaces, which successfully show contacting surfaces to a resolution of 6.4 mu m have been presented before. This paper overviews the validation of this technique, evaluates the main advantages and disadvantages compared to other techniques, and shows how this can be used to better understand the electrical contact interface.