The Thermal-Step-Technique applied to the study of charge decay in a film of polypropylene

The measurement of space charge location in insulating materials is necessary to know the residual electric field inside thick samples. So we have studied conduction phenomena and electric behaviour of these materials. The Thermal Step (T.S.) technique has been already used to measure the remaining electric field and space charge in polymers slabs in the thickness range 0.5 mm to 20 mm. In this work, we have extended this method to thin films. We have increased the speed of step and the acquisition. We present the results on 12 /spl mu/m polypropylene films. The applications concern power capacitors and interface contact problems (AL/PP).