Electrical resistivity in the titanium carbonitride-zirconia system

Abstract

A mixture of conductive titanium carbonitride and insulating partially stabilized zirconia powders was hot-press sintered, and a theoretical dense composite material obtained. The electrical conductivity as a function of C/N ratio and up to 50 vol % dispersed zirconia, partially stabilized by 3–5 mol % yttria, was studied. The Landauer model was tested. For low sintering temperatures (1500 °C), and with 3 mol % yttria in zirconia, titanium carbonitride particles present bad electrical contacts, and the transformation of tetragonal to monoclinic zirconia induces microcracking, therefore the Landauer model is not followed. On the other hand, for high-temperature (1700 °C) sintering, and using a fully stabilized zirconia powder with 5 mol % yttria, good electrical contacts between grains are established, thus the Landauer's model is confirmed. The high electrical conductivity of this insulator-conductive ceramic-ceramic composite allows an electric discharge machining.