The Failure of Lubricant Film

The failure of the fluid film at nano-scale and the relation between the failure point and pressure, velocity, and viscosity have been investigated [19]. The lubricants used in the experiments are given in Table 1. 

The failure of lubricant film is also related to characteristics of lubricants as shown in Fig. 44. Hexadecanethiol (C15H34S) film changes from EHL to TFL at the speed of 120 mm/s and no failure point appears in the speed range 

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In order to set up the relationship among the pressure, speed, and viscosity of lubricants without polar additives, Luo et al. [19] define the fluid factor L as  

The unit of Pf here is MPa is the kinetic viscosity of lubricant in mm /s u is the velocity in mm/s, for the oil without polar additives, k is 23.5 X 10 . If the tribo-pairs need to be lubricated with the fluid film in the TFL and EHL regime, the lubricant and the rolling speed should be chosen according to the pressure applied as Eq (9) so as to make that the liquid factor L is larger than the failure fluid factor L. Otherwise, the liquid film caimot be maintained under the pressure added. 

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