2012 Volume 37 Issue 1 Pages 11-14
The preparation of electrically conductive silicon nitride (Si3N4) ceramics by dispersing carbon nanotubes (CNTs) has been studied in the recent years. However, the density and strength of Si3N4 ceramics was found to deteriorate and the CNTs disappeared after firing at high temperatures because CNTs prevent Si3N4 from densification and there is a possibility that the CNTs reacted with the Si3N4 or SiO2. To prevent the CNTs from reacting and disappearing, low temperature densification is required. In this study, HfO2 was added to a Si3N4-Y2O3-Al2O3-AlN system to fabricate CNT-dispersed Si3N4 ceramics at low temperatures. As a result, a sample to which HfO2 had been added and which was fired at lower temperatures showed higher electrical conductivity and higher bending strength. It was also observed that the mechanical and electrical properties of the ceramics depended on the quantity of added CNTs.
