First Principles Studies of Adhesion and Adhesive Transfer at Aluminum-Graphite and Aluminum-Diamond Interfaces

Density functional theory was used to investigate adhesion and adhesive transfer at Al/diamond (Al(111)/C(111)-1x1, Al(111)/C(111)-2x1 and Al(111)/C(111)-1x1:H) and Al(111)/graphite(0001) interfaces. The work of separation, W$_{sep}$, was computed for each system and compared with that for other interfaces. Bond character was explored by plotting contours of the electron localization function (ELF). Adhesive transfer at the Al/diamond interfaces was investigated by subjecting each interface to a series of tensile strain increments up to fracture. For the Al/graphite interface, W$_{sep}$, was 0.11J/m$^{2}$, and the work of decohesion for a single layer of graphite transferring to aluminum, W$_{dec}$, was 0.077J/m$^{2}$. Although our theoretical framework does not include van der Waals forces that mitigate interlayer bonding between graphite sheets, the fact that W$_{dec} \quad <$ W$_{sep}$ suggests that it may be energetically favorable for one graphite layer to transfer to Al instead of separating right at the interface.