Investigation of the Atomic-Scale Friction of Boron Doped Diamond Using Molecular Dynamics
L Wang and B Shen and FH Sun, JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE, 11, 1550-1555 (2014).
Classical molecular dynamic (MD) simulations are performed to investigate the atomic-scale friction of diamond (111) surface in contact with boron doped diamond (111) surface sliding along the 11 (2) over bar crystallographic direction. Boron atoms are doped in the different layer near the interface with different doping levels. A tersoff potential is used to model the interactions between carbon and boron atoms. The results show that boron doping has little influence on the hardness of the diamond. Incorporating boron atoms in the first two layers of the diamond lattice count from the interface can affect the friction response significantly and lower the friction force. The friction force will lower as the doping level increase, but when the doping level exceeds a critical value of about 10000 ppm, the friction force will increase slightly. From calculating the vibrational energy of the B-C pair, we reveal that the boron carbide bonds would help change the surface frictional energy dissipation and thus lower the friction force. The results can interpret the macroscopic experiments results well that boron doped diamond films show lower friction coefficient than undoped ones although boron doped diamond films have larger grain size and rougher surface.
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