M.A. de la Rubia, Ceramic and Glass Institute (CSIC) and ETSI Telecommunication (UPM), Spain
Thick-film zinc oxide (ZnO)-based varistors have been prepared by screen-printing and tape-casting techniques. The manufacture of varistor thick-films by screen printing shows two critical problems: the excessive volatilization of Bi2O3 during the sintering step due to the exaggerated area–volume ratio of these devices and the lack of density of the green compacts, a problem inherent to screen-printing technology. Tape casting improves compact density and it is possible to include an additional press step before sintering. An electrical and microstructure comparison between thick-films prepared by both technologies ...