Effects of graphite nano-flakes on thermal and microstructural properties of TiB2–SiC composites

Abstract

In the last decades, the production of ultra-high temperature composites with improved thermo-mechanical properties has attracted much attention. This study focuses on the effect of graphite nano-flakes addition on the microstructure, densification, and thermal characteristics of TiB2-25 vol% SiC composite. The samples were manufactured through spark plasma sintering process under the sintering conditions of 1800 degrees C/7 min/40 MPa. Scanning electron microscopy images demonstrated a homogenous dispersion of graphite flakes within the TiB2-SiC composite causing a betterment in the densification process. The thermal diffusivity of the specimens was gained via the laser flash technique. The addition of graphite nano-flakes as a dopant in TiB2-SiC did not change the thermal diffusivity. Consequently, the remarkable thermal conductivity of TiB2-SiC remained intact. It seems that the finer grains and more interfaces obstruct the heat flow in TiB2-SiC-graphite composites. Adding a small amount of graphite nano-flakes enhances the densification of the mentioned composite by preventing the grain growth.