Cobalt-praseodymium-(lanthanum)-doped zinc oxide varistor prodn - giving low min. voltage and max. nonlinearity

摘要

In the prodn. of non-linear resistors (varistors) from ZnO and additives contg. metals, including one contg. Co, by mixing the starting materials, shaping by pressing, baking at 1100-1450 degrees C and providing with electrodes after cooling, the additives are 0.08-8.0 atom-% Pr and 0.1-8.0 atom-% Co and the temp. used is 1150-1400, pref. 1300-1350 degrees C. 0.08-8.0 atom-% La can also be added. The varistors are useful for the protection of various electronic devices, e.g. diodes, transistors or thyristors. The varistors have a low limiting voltage and max. non-linearity, the values depending on the temp. and amt. of additives used.