Design of lightweight and antioxidant SiCnws/SiC(Mox, rGO) nanocomposite from molybdenum-modified precursors for aerospace vehicle components

Making lightweight SiC composite ceramics with good load-bearing and remarkable surficial antioxidant capacity for use in thermal protection system is challenging. In this contribution, an ingenious strategy is reported to produce SiC(Mo x , rGO) nanocomposite polymer-derived ceramics (PDCs) for the first time by reactively re-pyrolyzing flexible polymolybdenumcarbosilane-vinyltriethoxysilane-graphene oxide (PMVG)/rigid SiC(Mo x , rGO) p fillers blends. Highly cross-linked PMVG precursors connect up to five polycarbosilane (PCS) to optimize their formability. In-situ formed MoSi 2 and Mo 4.8 Si 3 C 0.6 , compatible with β-SiC/SiO x C y /C free (rGO) matrix, can effectively strengthen interface bonding, promote nailing cracks, and even hinder β-SiC grain growth. More interestingly, using in-situ SiC nanowires (SiC nws ) by Mo-containing catalyst to decorate samples is an efficient route to reinforce the ceramic network, and SiC nws /SiC(Mo 0.1 , rGO) nanocomposite PDCs display optimal Vickers hardness (5.19 GPa), enhanced fracture toughness (4.26 MPa·m 1/2 ), high compressive strength (151.73 MPa), and low linear shrinkage (4.75%). Such products remain stability/integrity under flame scouring, their surface is covered by a dense SiO 2 passivation layer with good self-healing capacity owing to unique non-destructive oxides of embedded MoSi 2 /Mo 4.8 Si 3 C 0.6 . This work can further provide a feasible way to overcome the critical fabrication process in lightweight porous PDCs with well-balanced high load-bearing and good thermal insulation integration for aerospace vehicle components.