ZnO ceramics doped with small amounts of Bi2O3, CoO, MnO, Sb2O3 and Cr2O3 offer a great potential as electroceramic materials to be used as protectors to prevent electric surges. In the present communication, the reaction bonded alumina oxide (RBAO) technique is adapted for the production of ZnO-based ceramics by the reaction bonding zinc oxide (RBZnO) process with the idea of achieving the advantages of the RBAO process. Because Zn oxidation occurs between 330 degrees C and 468 degrees C, slow heating rates before the Zn melting point (419 degrees C) is very important in order to obtain the desired ceramic. The need for a fine microstructure of the matrix with many grain boundaries is discussed.

Keywords: milling; powders-solid state reaction; sintering; ZnO; varistors