Surface chemistry of chlorinated hydrocarbon lubricant additives - Part II: Modeling the tribological interface

In Part I (1), the concept of "Type I" antiseizure behavior for chlorinated hydrocarbons in extreme-pressure (EP) lubrication of ferrous metals was introduced; interfacial temperature measurements and surface analyses revealed that a solid lubricating layer consisting of ferrous chloride (FeCl(2)) and carbon prevents seizure and acts as a solid lubricant at less than similar to 1000 K. In this paper, careful measurement of the film growth and removal rates successfully rationalizes this tribological behavior. Thermodynamic calculations also show that iron carbides are favored at higher decomposition temperatures. Analysis of films formed from the thermal decomposition of carbon tetrachloride (CCl(4)) and chloroform (CHCl(3)) at similar to 1000 K using Mossbauer spectroscopy demonstrates that iron carbide is indeed formed in this case; tribological measurements also confirm this material as critical antiseizure material at high loads in "Type II" tribological behavior for chlorinated hydrocarbons with ferrous metals.