The corona poling apparatus consists of a heating stage (aluminum block) which acts also as the cathode. The sample is placed horizontally on the heating block and a 25 ìm thin tungsten wire is positioned 5 mm above the sample. The distance between the wire and the sample can be varied by several mm. The voltage can be up to 10 kV and the sample can be heated up to 300 oC. A glass-ceramic plate is placed between the sample and the wire to avoid charge sparks and a current break down.