ABSTRACT
Fluid lubricants may separate surfaces completely to avoid wear and minimize friction coe²cients to <0.1. ˜e most popular gaseous lubricant is air, because it is inexpensive, is abundantly available, and has no disposal issues. ˜e air turbine dentist drill is an example of air bearing technology, while many hydrostatic air bearings are being used in the construction of positioning equipment. Of the common gasses, hydrogen, ammonia, and ethane have viscosities about half that of air, and argon and oxygen have viscosities slightly higher than air. ˜e dynamic viscosity of air nearly doubles from room temperature to 250°C.
