Nanotribological Characteristics of Cu6Sn5, Cu3Sn, and Ni3Sn4 Intermetallic Compounds Developed by Diffusion Couples

Nanotribological characteristics, including coefficient of friction, wear coefficient, and wear resistance, of Cu₆Sn₅, Cu₃Sn, and Ni₃Sn₄ intermetallic compounds developed by annealing Sn-Cu or Sn-Ni diffusion couples were investigated in this work. The scratch test conditions combine a constant normal load of 10, 20, or 30 mN and a scratch rate of 0.1 1, or 10 mum/s. Experimental results indicate that as the normal load increases, the pile-up heightens and the scratch deepens, leading to greater coefficient of friction and wear coefficient while smaller wear resistance. Moreover, the scratch rate does not have a significant effect on the nanotribological characteristics except for Cu₆Sn₅ and Cu₃Sn under a normal load of 10 mN. Though hardness of Cu₆Sn₅, Cu₃Sn, and Ni₃Sn₄ is similar, Ni₃Sn₄ appears to be more prone to wear damage.