Dispersing two-dimensional (2D) graphene sheets in 3D material matrix becomes a promising route to access the exceptional mechanical and electrical properties of individual graphene sheets in bulk quantities for macroscopic applications. However, this is highly restricted by the uncontrolled distribution and orientation of the graphene sheets in 3D structures as well as the weak graphene-matrix bonding and poor load transfer. Here, we propose a previously unreported avenue to embed ordered 2D graphene array into ceramics matrix, where the catastrophic fracture failure mode of brittle ceramics was transformed into stable crack propagation behavior with 250 to 500% improvement in the mechanical toughness. An unprecedentedly low dry sliding friction coefficient of 0.06 in bulk ceramics was obtained mainly due to the inhibition of the microcrack propagation by the ordered 2D graphene array. These unique and low-cost 2D graphene array/ceramic composites may find applications in severe environments with superior structural and functional properties.

The stoichiometry of boron carbide thin films was controlled in the range of 0.1–8.9 via pulsed laser deposition by using boron-carbon dual-targets. The amorphous films sized 50 nm in thickness. The reaction rate of boron and carbon atoms increased with the increasing of target rotating speed. Carbon atoms preferentially substituted boron atoms within the chain site as sp2 hybridization at lower carbon concentrations and then within the icosahedrons site as sp3 hybridization at higher carbon concentrations.

Boron carbide ceramics were simultaneously synthesised and densified from B and C elemental powders by a spark plasma sintering method. The reactive sintering process was investigated, and two stages of large shrinkage corresponding to synthesis and densification of boron carbide were observed. At stage I (1300–1700°C), B reacted with C and the product in phase of free C and B rich boron carbide (B4+xC) was synthesised. With increasing the sintering temperature, C atoms diffused into the B4+xC lattice, resulting in the reduction in free C content and the decreasing in lattice parameters of B4+xC. At stage II from 1700 to 1900°C, the densification of the synthesised boron carbide occurred. The product was densified gradually and a high relative density (95%) was obtained by spark plasma sintering at 1900°C.

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