石墨烯增强SiC陶瓷界面结合的第一性原理计算

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

  • 摘要: 为提升SiC陶瓷复合材料的实际应用性能,研究其与石墨烯之间的微观界面结合机制已成为材料连接领域的热点课题,本文采用第一性原理计算方法,分别建立了由SiC极性和非极性表面建立的SiC(0001)-Si/石墨烯/SiC(0001)-Si和SiC(11 \bar2 0)/石墨烯/SiC(11 \bar2 0)界面模型,并研究了其界面的结合情况。结果表明:在由SiC极性表面建立的界面模型界面处,结合Mulliken布居分析,C、Si原子均以共价键和离子键混合形式成键,且C38-Si17键、C58-Si70键和C54-Si66键的共价性均强于离子性,而在由SiC非极性表面建立的界面模型界面处,C、Si原子并未成键。比较两种界面模型的界面分离功,结果显示SiC(0001)-Si/石墨烯/SiC(0001)-Si界面分离功最大值为0.14 J/m2,SiC(11 \bar2 0)/石墨烯/SiC(11 \bar2 0)界面分离功最大值仅为0.01 J/m2,而前者对应界面间距4.21 Å反而明显大于后者3.10 Å,这表明SiC极性表面与石墨烯结合作用效果更明显,更具有强界面特征,更能有效提升SiC陶瓷的应用性能。

     

    Abstract: 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.

     

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