RESEARCH ON LIQUID FILM SURFACE FORCE CONFINED WITHIN NANO-METER SPACING AND ITS EFFECT ON SURFACE CONTACT

纳米级间距内液膜表面力及其对表面接触影响的研究

• 批准号: 11650153
• 负责人: BO Zhang
• 金额: $ 2.24万
• 依托单位: SAGA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650153/
• 关键词: Nanotribology; Surface force; Laplace pressure; nano film; Meniscus; Micromachine; Magnetic Recording; Laplace pressure measurement

The deformation of solid surfaces caused by the Laplace pressure is analyzed and its effect on the ^meniscus force measurement on a surface force apparatus is discussed. It is found theoretically that the deformation reaches several nano meter orders and reduces greatly the meniscus force when the meniscus curvature radius is small. It is concluded that the deviation of the measured meniscus force with the surface force apparatus from equation F=4πγRcosθ for nano meter meniscus may be neither due to the hydrogen bonding interaction, nor the short range solid-solid interaction. The main reason lies in the deformation of the solid surface due to the Laplace pressure. The nano meter deformation of solid surfaces caused by the Laplace pressure is of great importance in measurement of the meniscus force.In addition to the surface deformation, van der Waals force is also considered as a contribution to the pull-off force. As a result, it is found that the pull-off force will depend greatly o … More n the vapor pressure around the solid surfaces.As a solution to reduce the effects of solid surface deformation on the measurement of the pull-off force, a new method of direct measurement of the Laplace pressure was proposed, measuring device was designed, and measurement was conducted on the new device. Satisfactory agreement between the Experimental and theoretical results was obtained.In addition to the basic studies mentioned above, the effect of surface force on the performance of slider air bearing of magnetic head in hard disc systems was analyzed with respect to the glide avalanche. The numerical results show that surface force reduces the stiffness of the slider air bearing and the load carrying capacity as well. It is worth noting that, although the decrease in the load carrying capacity may not be significant, the reduction in the stiffness may be critical for many cases. The reduction in the stiffness of slider air bearings due to the surface force may be one of the most important mechanisms of the glide avalanche. The predicted take-off height to overcome the surface force is about several nano-meters. Increasing the pitch angle tends to decreases the take-off height. A lubricant film of about 1 nm will reduce the risk of the glide avalanche in some extent, but increasing the film thickness has little effect. Less

分析了由拉普拉斯压力引起的固体表面变形，讨论了拉普拉斯压力对表面力仪上半月板力测量的影响。从理论上发现，当半月板曲率半径较小时，变形达到几个纳米量级，大大降低了半月板力。结果表明，表面力仪测量的纳米半月板力与方程F=4πγRcosθ的偏差既不是氢键相互作用的结果，也不是近程固-固相互作用的结果。其主要原因是由于拉氏压力引起固体表面的变形。由拉普拉斯压力引起的固体表面纳米级变形在半月板力的测量中具有重要意义。除了表面变形外，范德华力也被认为对拉脱力有贡献。结果发现，拉离力在很大程度上取决于固体表面周围的蒸汽压。为减小固体表面变形对拉拔力测量的影响，提出了一种直接测量拉拔压力的新方法，设计了测量装置，并在新装置上进行了测量。实验结果与理论结果吻合较好。在上述基础研究的基础上，分析了表面力对硬盘系统磁头滑块气轴承滑块性能的影响。数值计算结果表明，表面力降低了滑块气轴承的刚度和承载能力。值得注意的是，虽然承载能力的降低可能并不显著，但刚度的降低在许多情况下可能是至关重要的。滑块空气轴承在表面力作用下刚度降低可能是滑块雪崩发生的重要机制之一。预计克服表面力的起飞高度约为几纳米。增加俯仰角会降低起飞高度。1 nm左右的润滑膜可以在一定程度上降低滑行雪崩的风险，但增加润滑膜的厚度效果不大。少

项目成果

Bo Zhang, and Akira Nakajima: "Analytical Study of Stiffness of Meniscus Bridge"Tribologist, J. of Japanese Society of Tribologist. 46. 243-250 (2001)

张波、中岛晃：“半月板桥刚度的分析研究”摩擦学家，日本摩擦学会J.。

張波,中島晃: "メニスカスのばね係数に関する理論解析"トライボロジスト. 46・3(掲載予定). (2001)

Changha，Akira Nakajima：“弯月面弹簧系数的理论分析”摩擦学家46·3（待出版）。

張 波, 中島 晃: "メニスカスのばね係数に関する理論解析"トライボロジスト. 46・3. 243-250 (2001)

张博，中岛晃：“弯月面弹簧系数的理论分析”摩擦学家46・3。

Bo Zhang, Akira Nakajima: "Direct Measurement of the Laplace Pressure in a Very Thin Liquid Film"Journal of Colloid and Interface Science. 245. 215-218 (2002)

张博，中岛晃：“直接测量极薄液膜中的拉普拉斯压力”胶体与界面科学杂志。