Effects of pressure and velocity on the interface friction behavior of diamond utilizing ReaxFF simulations
Reaxff MD models chemical mechanical polishing-style diamond friction with varying normal load (pressures in the ~10 GPa class in the figures) and sliding velocity (20, 50, 100 m s⁻¹ along x for ~500 ps in the stated setup), monitoring friction force, C–C / C–O–C bond populations, and amorphous carbon formation.
Summary¶
The study couples rigid top diamond on hydroxylated diamond + H₂O₂ slurry in LAMMPS NVT at 300 K with Berendsen thermostat (25 fs damping), 0.25 fs time step, and ~12–14 GPa-class normal pressures in the cited figures; friction trends vs C–C/C–O–C bonds and amorphous C fraction evolve in two regimes with pressure and sliding velocity.
Methods¶
1 — MD application. LAMMPS; combustion-class C/H/O Reaxff for diamond + aqueous CMP-like chemistry (Section 2). NVT at 300 K; Berendsen thermostat; 25 fs damping; velocity Verlet; 0.25 fs time step; rigid top layer + shear over hydroxylated diamond + H₂O₂ slurry (Section 2). Normal pressures ~12–14 GPa (figures); sliding 20, 50, 100 m s⁻¹ +x; ~500 ps after load ramp (Section 2–3). PBC in x,y in the in-plane slab geometry; N/A — NPT (constant-T NVT with mechanical load control instead of barostat in excerpt). N/A — metadynamics; N/A — E-field (no external field in excerpt). N/A — replica exchange (not used).
2 — Force-field training. N/A — Reaxff from cited combustion CH/O line; not refit in-manuscript.
3 — Static QM. N/A
4 — Review or non-simulation. N/A
Findings¶
Outcomes and mechanisms. Early friction rises with C–C and C–O–C interfacial bonds and with higher normal pressure and sliding velocity in the first regime described. Later friction correlates with amorphous carbon and can drop with increasing pressure/velocity in the second regime (interpretation in article). Removal mechanisms shift from dominant C–C single-bond formation at low pressure to more single and multi-C–C bonds at higher pressure (wear + subsurface damage narrative in text).
Comparisons and sensitivity. Pressure and sliding velocity sweeps; friction vs bond counts vs a-C fraction (figure-based parameter study).
Authored limitations and outlook. Reaxff slurry chemistry is simplified vs full electrochemistry; see ## Limitations on this page.
Corpus honesty. Manuscript 2020 vs IJMS 2021 issue—DOI is authoritative; slugs may retain “2020” naming (see ## Citations below).
Limitations¶
Reaxff C/O/H chemistry for CMP slurry may omit full electrochemical detail; simulation speeds/pressures map to idealized interface models.
Relevance to group¶
van Duin co-authorship; Reaxff tribology on diamond manufacturing interfaces.
Citations and evidence anchors¶
- DOI:
10.1016/j.ijmecsci.2020.106096(published IJMS 191, 2021; manuscript numbering may differ from 2020 slug)