Microstructure and Fracture Mechanism Investigation of Porous Silicon Nitride–Zirconia–Graphene Composite Using Multi-Scale and In-Situ Microscopy

Silicon nitride–zirconia–graphene composites with high graphene content (5 wt.% and 30 wt.%) were sintered by gas pressure sintering (GPS). The effect of the multilayer (MLG) on microstructure fracture mechanism is investigated multi-scale in-situ microscopy. Multi-scale microscopy confirms that phases disperse evenly in without obvious agglomeration. MLG flakes well dispersed between ceramic matrix grains slow down phase transformation from α to β-Si3N4, subsequent needle-like growth β-Si3N4 rods densification due reduction additives particularly case MLG. size distribution Si3N4 shifts towards a larger range increase 5 wt.%, while higher (30 hinders ZrO2 phase. composite has porosity 47%, one exhibits approximately 30%. Both Si3N4/MLG show potential resistance contact or indentation damage. Crack initiation propagation, porous microstructure, shift are observed using transmission electron crack propagates through ceramic/MLG interface both non-ceramic components low content. However, prefers bypass