The conditions inside the contact are, however, different due to the pressure effect on viscosity and density of the lubricant, which is different for different lubricants. It is probably because of this effect that the maximum pressure, which is the film pressure divided by the maximum Herzian pressure, shown by [C8C1 im]PF6 is not highest even though the lubricant viscosity at atmospheric
pressure is highest. The numeric values for the effective viscosity max. contact pressure and min. film thickness for the Al–Steel smooth contact lubricated with the lubricants is given in Table 3.