Low shear strength (30 MPa) organic films were grown in situ on Pt_0.9Au_0.1 surfaces via cyclic sliding contact in dry N₂ with trace concentrations of ambient hydrocarbons. We present a systematic investigation of the stress- and time-dependent film formation. Steady-state friction coefficients were found to be as low as µ ~ 0.015 and inversely proportional to contact pressure, revealing non-Amontonian behavior. Above a Hertzian contact pressure of ~500 MPa, shear strength dropped, indicating an activated process. Raman spectroscopy identified non-uniformity in areal coverage and relative order with contact pressure. Regions of steady-state low-friction behavior exhibited spectra similar to DLC coatings. Atomic force microscopy was used to study the formation and growth of films at the nanoscale. Stress- and time-dependent measurements suggested a sublinear increase of film volume with time, and a transition from growth to wear at a Hertzian contact pressure of ~1.2 GPa.

在干燥 N _{2 中}通过循环滑动接触在Pt _0.9 Au _0.1表面原位生长低剪切强度 (30 MPa) 有机薄膜含有痕量浓度的环境碳氢化合物。我们对应力和时间相关的薄膜形成进行了系统的研究。发现稳态摩擦系数低至 µ ~ 0.015，与接触压力成反比，揭示了非阿蒙顿行为。高于~500 MPa 的赫兹接触压力，剪切强度下降，表明过程被激活。拉曼光谱确定了区域覆盖的不均匀性和接触压力的相对顺序。稳态低摩擦行为区域表现出类似于 DLC 涂层的光谱。原子力显微镜用于研究纳米级薄膜的形成和生长。与应力和时间相关的测量表明，薄膜体积随时间呈亚线性增加，并且在赫兹接触压力约为 1 时从生长过渡到磨损。