To understand the chemical behaviour of lubricant components during boundary lubrication, a general concept of negative ionradical reactive intermediates formation for these components has been proposed. The concept is based upon the ionisation mechanism of these compounds caused by the action ofelectrons of law energy (1-4 eV). Electrons of such energy (exoelectrons) are spontaneously emitted from most fresh surfaces formed during friction. The principal thesis of the model is that lubricant components form anions which are then chemisorbed on the positively charged areas of rubbing surfaces.The formation of negative ions and their decomposition process are simulated by electron attachment mass spectrography. This type of mass spectrography uses electrons of a n energy range similar to those of exoelectrons. The proposed model encompasses the following major stages: (a) low-energy electron emission process and creation of positively charged spots, (b) action of emitted electrons with lubricant components (anion and radical formation), (c) reactions of anions with metal surfaces forming a film protecting the surface from wear, (d) cracking of chemical bonds producing other radicals. The model explains many lubrication phenomena of hydrocarbons, oxygencontaining compounds, and many types of chemicals used as antiwear and extreme-pressure additives.
AbstractKeywords electron emission, anions, chemisorption, protective film, boundary lubricationThe most important group of lubricants includes lubricating oils, formulated base fluids, and additives. The base fluids indude petroleum hydrocarbons and/or synthetic materials. The additives encompass many chemicals, especially polar ones.Organic compounds containing such elements as S, 0, C1, P, N, as well as organometallic compounds, are the commonly used boundary lubrication additives.
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