Free chlorine fixation and the protective film in boundary lubrication

Wax chloride is an older type of additive which releases free chlorine when it is hydrolysed or when it is in conditions of boundary lubrication. The chlorine forms a protective film of ferro-chloride but, on the other hand, it severely rusts the iron, the main reason for its discontinuance since the 1960s. In this paper epoxy plant oil is recommended as a means to absorb effectively and fix the free chlorine, then transform it into chlorohydroxyl oil and polyether. Rust corrosion can be controlled, and the absorbent transformed into a ferro-chloride protective film on the frictional surfaces of the iron during rubbing. The free chlorine can thus be transformed directly into a protective film. With a dynamic test for the reaction of absorption HCl, a friction test, an anti-rust test, electron spectroscopy and infrared spectroscopy analysis, the underlying principles and effects of chlorine fixation have been confirmed. This method has been applied to cold squeezing, and tested with EP industrial gear oil. The price of wax chloride is much less than the standard additive containing sulphur and phosphorus, and its properties are almost the same. It is concluded that wax chloride could still be viable for use in lubricants.