Shear and thermal effects in boundary film formation during sliding

• Autores: Furlong, Octavio Javier; Miller, Brendan Paul; Kotvis, Peter V.; Adams, Heather; Tysoe, Wilfred T.
• Año de publicación: 2014
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: SHEAR-INDUCED; BOUNDARY-FILM; THERMAL EFFECTS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

A prerequisite for understanding mechano- and tribochemical reaction pathways is that the interface be in thermodynamic equilibrium and that the temperature be well defined. It is suggested that this occurs in two regimes: when the surfaces are only slightly perturbed during sliding, leading to negligible frictional heating, and when the surface temperatures are very high (1000 K), in the so-called extreme pressure regime. The tribochemistry occurring in each regime is discussed in terms of the elementary steps leading to tribofilm formation, namely (i) a reaction of the additive or gas-phase lubricant on the surface to form an adsorbed precursor, (ii) decomposition of the molecular precursor, (iii) a process that causes the formation of a tribofilm that (iv) regenerates a clean surface that allows this tribochemical cycle to continue to form a thicker film. These steps are thermally driven in the extreme-pressure regime, while under milder conditions, they are induced by interfacial shear. In intermediate situations, the processes are likely to be a combination of those occurring at the extrema.
Fil: Furlong, Octavio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; Argentina
Fil: Miller, Brendan Paul. Chevron Oronite Company LLC; Estados Unidos
Fil: Kotvis, Peter V.. University Of Wisconsin; Estados Unidos
Fil: Adams, Heather. University Of Wisconsin; Estados Unidos
Fil: Tysoe, Wilfred T.. University Of Wisconsin; Estados Unidos