DEVELOPMENT OF SPECIMEN HOLDERS FOR MEASURING ELECTRICAL-PROPERTIES OF OXIDES UNDER ELECTRON-IRRADIATION IN HVEM

Two types of specimen holders have been developed for in situ measurem ents of electrical properties during microstructural observation in a high voltage electron microscope (HVEM). Each specimen holder contains an electrode cell consisting of electrodes, a heater, a thermocouple and a base made from MACOR insulating ceramic. The temperature depende nce of the electrical conductivity in ZrO2-3mol% Y2O3 (YSZ) and the di electric loss in MgO have been investigated without irradiation for ev aluating the reliability and the limitation of the specimen holders. Y SZ specimens were irradiated with 1 MeV electrons at temperatures from 450 K to 870 K in the HVEM. The radiation induced electrical conducti vity was detected by in situ measurements. The dielectric loss in MgO was also measured and found to increase under electron irradiation.