Fig. 11

Lifshitz-van der Waals and AB components of the surface energy deduced from contact angle measurements using several liquids deposited on the surface of Al-based compounds. The open square is for single crystalline alumina and the cross for aluminium metal equipped with its native oxide. The dotted line guides the eye between the data for alumina and for fcc-Al. Observe that all Lifshitz-van der Waals data points fall in a range below the value for bulk alumina and close to that of the pure, oxidized metal whereas all values of the AB component are clearly below that of the (oxidized) metal, and far below that for alumina. The specimens that exhibit a vanishingly small AB component are the most complex ones and include the quasicrystalline i-ACF and i-APM samples