In the present study, we demonstrated a novel process of in-situ fabrication of graphene sheets by adopting the chemical vapor deposition (CVD) method. Fabricating such a layer of vertical graphene sheets (VGs) on the surface of microcrystalline diamond (MCD) films could decrease the stable coefficient of friction (COF) by 20–30%. Besides, such lubricity showed excellent load capacity and durability. With normal loads ranging from 3 N to 9 N (Hertz contact pressure of 2.1–3.1 GPa), the MCD-VGs films exhibited COFs stabilized at 0.105 and wear rates less than 5 × 10⁻⁶ mm³ N⁻¹ m⁻¹. Additionally, the produced VGs displayed an excellent service lifetime with 72,000 sliding cycles. During the friction tests, an equilibrium graphene self-mated contact formed on the sliding interface as graphene fragments adhered onto the counterpart ball and resulted in the reduction of friction and low wear rates. Additionally, the mixtures of Si₃N₄/SiO₂ particles and graphene sheets residual within the wear tracks would promote the transformation of the sliding regime to three-body abrasion, beneficial for friction reduction. The findings presented in this study provide a novel and effective approach to enhance the lubricity of any engineering diamond surface.

在本研究中，我们展示了一种采用化学气相沉积 (CVD) 方法原位制造石墨烯片的新工艺。在微晶金刚石 (MCD) 薄膜表面制造这样一层垂直石墨烯片 (VG) 可以将稳定摩擦系数 (COF) 降低 20-30%。此外，这种润滑性显示出优异的负载能力和耐久性。法向载荷范围为 3 N 至 9 N（赫兹接触压力为 2.1-3.1 GPa），MCD-VGs 薄膜的 COF 稳定在 0.105，磨损率小于 5 × 10 ^-6  mm ³  N ^-1  m ^-1. 此外，所生产的 VG 具有 72,000 次滑动循环的出色使用寿命。在摩擦测试期间，当石墨烯碎片粘附在配对球上时，在滑动界面上形成了平衡石墨烯自配对接触，导致摩擦降低和磨损率降低。此外，磨损轨迹内残留的Si ₃ N ₄ /SiO ₂颗粒和石墨烯片的混合物将促进滑动状态向三体磨损的转变，有利于减少摩擦。本研究中提出的发现提供了一种新颖有效的方法来增强任何工程金刚石表面的润滑性。