Influence of valence electron concentration over friction coefficient of B2-based approximants

According to the valence electron concentration e/a criterion for approxima nts, some B2 superstructures may be regarded as a special group of approxim ants. The present paper reports on an investigation of the friction behavio r of this group of phases. The results are compared with data specific to q uasicrystals. We show that samples containing the B2 structure and its supe rstructures exhibit friction coefficients that decrease with increasing ela and reach minimum at e/a=1.86, i.e. where the quasicrystal is stable. Ther efore, the B2-based approximants and quasicrystals belong to a group of pha ses whose surface properties are mainly determined by electronic structure rather than crystal structure. (C) 2000 Elsevier Science B.V. All rights re served.