Screen printed electro-conductive ceramics

Screen printed, electro-conductive ceramic thick-films were developed for the use as resistance heating elements. Two particulate composites, Al2O3/TiN and Si3N4/TiN, as well as a single phase material, indium-tin-oxide, were selected for this purpose and were characterized with respect to their microstructures and their electrical properties. For the use as thick-film heating elements it was necessary to develop microstructures with high densities. In case of the composite materials the variation of the electrical conductivity in dependence of the ratio of conducting to insulating phase could be described by the percolation theory. The percolation threshold of these thick-films is influenced by the film thickness which is an effect of the transition region between the three dimensional and the two dimensional case. An application for the electro-conductive ceramic films is their use as high temperature heating elements. Different devices were realized and operated up to temperatures of 1000 °C.