Microstructure and mechanical properties of pitch based mixture modified by additions of graphene oxide precursor and TiB2 particles

Abstract

Pitch based mixture as binder material is crucial component for structure stability and mechanical properties of carbon/graphite electrodes. In this work, coal tar pitch (CTP) mixture was modified by additions of graphene oxide (GO) precursor and fine TiB2 particles. It is found that 1 wt.%GO addition increases the crystallite size, La value and reduce the defects density of (002) planes in CTP mesophase and carbonization products with increased elastic modulus. The additions of 3 or 5 wt.%TiB2 increase the stacking height of (002) planes (Lc) of CTP pyrolysis and carbonization products with increased edge dislocation density and ultimate strain. The combined additions of TiB2 and GO generate a synergistic effect on further improving the mechanical properties of CTP carbonization products with increasing the stacking order of (002) plane, crystallite size (La and Lc) and edge dislocation density. CTP-1GO-5TiB2 shows a compressive strength 194.7 MPa higher than the pure CTP (155.4 MPa). Further findings suggest that a combined mechanism of GO and TiB2 additions can be established through stabilizing C–C bonds while reducing C-O bonds along with chemical component transformations after pyrolysis and carbonization. TiB2 particles play a key role in making the synergistic effect on improving the mechanical strength and reducing the oxidation of C–C bonds with additional increase in La value.