润滑分子特性对纳米级流体膜失效的影响

为研究 nm级流体膜的失效情况 ,采用 NGY- 2型nm级膜厚测量仪 ,根据光干涉相对光强原理 ,对纯滚动点接触的中心区进行润滑膜厚度测量。观察不同载荷和速度下纯烷烃及加入少量酸时的流体膜厚度的变化情况 ,考察流体效应膜的失效情况。实验表明 :使用烷烃作润滑剂时 ,当压力增至某一定值时有一个临界点 ,当速度低于此点时 ,膜厚剧减 ,此时润滑膜不再具有流体特征 ,此点是润滑膜失效点 ,它与压力、速度、润滑剂的粘度以及分子极性有关。加入少量极性添加剂后所形成的润滑膜可承受较大的载荷 ,并能确保nm级流体膜不失效 ;在较高压力下 ,要在接触区形成流体膜就必须施加更高的速度或使用较大粘度的润滑剂 ;极性添加物的加入能提高流体膜的承载能力

Effect of the characteristics of lubricant moleculeson on the failure of nano-fluid films

Failure of nano fluid films was studied by using a NGY 2 nano film thickness measurer with the relative optical interference intensity technique to measure the film thickness in the point contact region in a pure rolling system. The failure of the hydrodynamic film was studied with lubricants using highly purified alkanes and mixture of those and fatty acids for different velocities and pressures. The experimental data for the highly purified alkanes shows that the film thickness suddenly decreases when the pressure increases to a certain level. Once the rolling speed decreases anymore, the film does not have any hydrodynamic properties and the hydrodynamic film fails. The failure of the nano fluid film is related to the pressure, the velocity, the lubricant viscosity and the polarity of the molecules. When a fatty acid is added to the highly purified alkanes, the nano fluid film does not fail for the experimental condition. For higher pressures, higher speeds or larger viscosities are needed to form the fluid film. Polar additives can improve film properties so that it can be maintained at much lower velocities and higher pressures than the lubricant without any additives.