First-principles calculations of interfacial bonding in graphene-enhanced SiC ceramics

In order to improve the practical application performance of SiC ceramics composites, the research on the micro interface bonding mechanism between SiC ceramics composites, and graphene has become a hot topic in the field of material bonding. In this paper, based on the first principles calculation method, the SiC(0001)-Si/graphene/SiC(0001)-Si and SiC(11\bar 20)/graphene/SiC(11\bar 20) interface models based on the polar and non-polar surfaces of SiC were established respectively, and the interface bonding was studied. The results show that at the interface of the interface model established by SiC polar surface, C and Si atoms are bonded in the form of covalent bonds and ionic bonds, as analyzed by Mulliken population analysis. And the covalent properties of C₃₈-Si₁₇ bonds, C₅₈-Si₇₀ bonds and C₅₄-Si₆₆ bonds are stronger than that of ionic bonds, However, at the interface of the interface model established by the SiC non-polar surface, C and Si atoms are not bonded. Comparing the interfacial separation work of the two interface models, the maximum value of the interfacial separation work for the SiC(0001)-Si/graphene/SiC(0001)-Si interface is 0.14 J/m², while that for the SiC(11\bar 20)/graphene/SiC(11\bar 20) interface is only 0.01 J/m². However, the former has a larger interface spacing of 4.21 Å compared to the latter's 3.10 Å. This indicates that the bonding interaction between the SiC polar surface and graphene is more pronounced, with stronger interface characteristics, and is more effective in enhancing the application performance of SiC ceramics.