The shear force of oil film containing an oiliness additive in a narrow gap was measured with a newly developed parallel‐disk viscometer supported by an aerostatic thrust bearing. To evaluate viscometer performance, the shear force of pure base oil was first measured using an oleophobic coated disk. Using the coated disk resulted in interfacial slip between the disk surface and oil, which significantly reduced the shear force compared with that when a noncoated disk was used. Next, the shear force of base oil containing an oiliness additive was measured without using the coated disk. Again it was significantly reduced, especially when the gap was less than 1 μm. The degree of reduction depended on the oiliness additive used. These results demonstrate that an oiliness additive can cause interfacial slip, resulting in friction reduction even in a hydrodynamic lubrication regime with a submicrometer gap.

中文翻译：

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用空气轴承支撑的新型平行圆盘粘度计测量含油性添加剂的油膜的窄间隙剪切性能

使用新开发的由空气静力推力轴承支撑的平行圆盘粘度计测量在狭窄间隙中包含油性添加剂的油膜的剪切力。为了评估粘度计的性能，首先使用疏油涂层圆盘测量纯基础油的剪切力。与使用非涂层圆盘相比，使用涂层圆盘会导致圆盘表面与油之间的界面滑动，从而显着降低了剪切力。接下来，在不使用涂覆圆盘的情况下测量了包含油性添加剂的基础油的剪切力。再次明显减小了间隙，尤其是当间隙小于1μm时。还原程度取决于所用的油性添加剂。这些结果表明，油性添加剂会引起界面滑移，