Reaction pathways and kinetics in the degradation of forging lubricants

The stability of a hot forging lubricant determines its effectiveness durin g operation. Aqueous lubricants, which are increasingly popular because of environmental issues, contain an organic ingredient, a stabilizer, and othe r species including biocides and corrosion inhibitors. The stability of a m odel forging lubricant containing dipotassium o-phthalate and sodium silica te in water has been measured over a wide range of temperatures and initial concentrations. The oxidation of the organic species is correlated using k inetic analysis, which reveals that decomposition occurs through a first-or der reaction with an activation energy of approximate to 58.2 kJ/mol. The k inetic result is consistent with a proposed free radical reaction mechanism that is also shown to be consistent with theoretical calculations and resu lts reported for other types of lubricants.