Non-destructive testing of materials using a novel electric potential sensor

In this paper we present new results using a novel electric potential sensor to image non-invasively faults in metal samples. This new technique measures the surface potential due to an A C current flowing in the sample via capacitive coupling. The more resistive the material the easier it is to create a measurable potential gradient. This makes the method particularly suitable for composites such as carbon fibre or ceramic based materials where conventional techniques are less effective. We present initial results for samples of stainless steel with machined faults on the reverse side. It is envisaged that in many cases this would be used in conjunction with other techniques in a data fusion system for example with eddy current sensing to provide complementary data. Such multi-sensor systems would enhance the probability of fault detection while at the same time reducing the number of false positive responses.