TAPE CAST RARE-EARTH OXIDE-DOPED ZNO VARISTOR

Praseodymium oxide-doped zinc oxide varistor strip elements have been made by tape casting to a thickness Of 0.5-0.6 mm followed by sinterin g. These varistors have a low breakdown voltage, of around 40 V with f ields of 1.4-1.6 V/grain and a non-linearity coefficient of 30. The th ickness of the varistors was increased by stacking tape cast layers be fore firing. The I-V characteristics, microstructural features and the resistivity of such tapes, as a function of frequency, are reported. It is suggested that tape casting is a simple method to obtain low vol tage ZnO varistors. (C) 1993 The Institute of Materials.