Tribology of plane strain compression tests on aluminium strip using ToF-SIMS analysis of transfer films

The electrode potential of freshly generated aluminium surfaces in lubricating oil

“…Which one predominates is not yet known, since both reactions would accelerate the anodic reaction by providing an added cathodic reactant. In this connection, it is of note that secondary ion mass spectroscopic analysis of the rolled surface shows fragments that can be associated with aluminium soap [15], consistent with the observations described above and the interpretation via reactions (1) or (2) or variations thereof. We believe that this is the first time that the electrode potential of these denuded surfaces has been measured under immersion in a lubricant system, and the role of lubricant additives observed.…”

Friction and material transfer in micro-scale sliding contact between aluminium alloy and steel

“…In lubricated conditions, both the magnitude and the variation of the friction coefficient with the number of test cycles (cf. figures 6, 9 and 10) are similar to that observed on conventional scale measurements at low speeds [13][14][15]. This indicates that the scale effect is not significant in the presence of oil.…”

“…The results show that the friction coefficient is reduced when the boundary additive is included, for both as-received and polished samples. This is similar to the trend observed in twist compression tests [13] and PSCTs [14,15]. Although the morphology of the transfer film is similar to that observed in the tests with the base oil, the transfer film is more easily wiped off with paper.…”

“…A slurry-like transfer film reduces the friction coefficient while a strongly adhered material on the tool degrades the tool surface and leads to the increase in friction [2,12,13]. Recent measurements of friction [14,15] for plane strain compression tests (PCST) on aluminium strip show that the friction coefficient may decrease with the development of a transfer film in the presence of a reactive boundary additive. Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) analyses of tool and strip surface on PSCTs confirm that the transfer film is composed of organo-metallic compounds [14,15], as previously reported in cutting or rolling processes [16,17].…”

“…Recent measurements of friction [14,15] for plane strain compression tests (PCST) on aluminium strip show that the friction coefficient may decrease with the development of a transfer film in the presence of a reactive boundary additive. Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) analyses of tool and strip surface on PSCTs confirm that the transfer film is composed of organo-metallic compounds [14,15], as previously reported in cutting or rolling processes [16,17]. By contrast the transfer film formed under dry condition or with base oil is usually a strongly adhered material, and no decrease in friction is observed [15].…”