First principles study of the aluminum-cubic boron nitride interface

A plane wave density functional methodology, with the local density approximation for the elemental constituents, was used to investigate the structure, bonding, and adhesion of atomic-scale interfaces between aluminum and cubic-boron nitride (c-BN). Two fully periodic interfaces, Al(110)-c-BN(110) and Al(001)-c-BN(110), were constructed for this purpose. Interfacial bonding, examined with contours of the charge density difference and electron localization function, was found to be stronger between Al-N pairs than Al-B pairs. The computed work of separation (W_s) values were 2.25 J/m² for Al(110)-c-BN(110) and 2.65 J/m² for Al(001)-c-BN(110). The higher adhesion in the latter interface is attributed to a higher planar density of interfacial Al atoms. The computed W s values were compared with values from first principles calculations on other aluminum-ceramic interfaces. The possibility of adhesive transfer during tensile debonding was qualitatively investigated.