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Geometrically complex, three‐dimensional (3‐D) structures of SiC were produced by a colloidal printing method known as robocasting, followed by low‐pressure spark plasma sintering (SPS) to produce dense ceramic bodies. A concentrated, aqueous colloidal ink consisting of SiC, Al2O3, and Y2O3 particles in a dilute polymer solution with a total solids volume fraction of 0.44 was developed to have pseudoplastic behavior with yield stress rheology. Lattice structures consisting of extruded filaments deposited in an overall cylindrical or cuboid shape were printed through nozzles ranging in diameter from 150 to 330 μm. After printing, drying and calcining processes, the structures were sintered at 1700°C in argon by SPS. The final average grain size was 1–2 μm and samples displayed above 97% of theoretical density, showing ~22.8% linear shrinkage from green to sintered state.

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a b s t r a c tThe role played by graphene in the friction and wear behaviour of graphene/silicon carbide (SiC) composites, tested under dry sliding conditions and using silicon nitride balls as counterbodies, is investigated as a function of the graphene nanoplatelets (GNPs) content and the graphene source. GNPs composites show an enhanced wear resistance as compared to monolithic SiC, with maximum improvements of ∼70% for the material containing up to 20 vol.% of GNPs; whereas the friction performance depends on the sliding distance and GNPs content. The analysis of the wear debris by micro-Raman spectroscopy evidenced that the tribological behaviour of the GNPs/SiC materials is linked to the formation of an adhered lubricating and protecting tribofilm. Multilayered graphene fillers participate more actively in the protecting tribofilm than other graphene sources such as reduced graphene oxide or in-situ grown graphene flakes.

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