Abstract
Densification evolution has been analysed in liquid phase assisted spark plasma sintering (SPS) of silicon nitride (Si 3N 4)-based materials. Monolithic ceramics with variable amounts of Al 2O 3/Y 2O 3 sintering additives, and carbon nanotubes (CNTs) containing Si 3N 4 composites have been considered. The shrinkage behaviour of SPSed monolithic Si 3N 4 showed a noticeable enhancement of the particle rearrangement stage, exhibiting a complete wetting of the grain boundary phase even for the lowest additive content (1.70 vol.%), unlike the corresponding hot pressed (HPed) material. An improvement of the liquid phase wetting by the presence of electromechanical forces is proposed to explain the enhanced densification occurring in the particle rearrangement stage of the SPS process. Furthermore, the addition of CNTs seems to increase the efficiency of this mechanism, decreasing the particle rearrangement temperature.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
