Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 9: Nanotribology
O 9.8: Talk
Monday, March 11, 2013, 12:15–12:30, H42
Chemical effects on the frictional characteristics of Pt(111) and a Pt-based metallic glass — •Arnaud Caron1, Dmitri V. Louzguine-Luzgin2, and Roland Bennewitz1 — 1INM - Leibniz-Institute for New Materials, Saarbrücken, Germany — 2WPI-Advanced Institute of Materials Research, Tohoku University, Sendai, Japan
Nanometer-scale friction measurements on a Pt(111) surface and a Pt-based metallic glass surface have been performed in ultra high vacuum and at room temperature by using oxidized silicon and diamond coated silicon AFM-tips as counter bodies. Neither the load dependence of friction nor its velocity dependence are affected by the structural difference between the Pt(111) and the Pt-based metallic glass surfaces. However, we find that the friction forces greatly depend on the chemistry of the counter body, i.e. SiO2 or diamond. For the SiO2/Pt(111) and SiO2/Pt-based MG friction couples we measure a friction coefficient COF = 0.05. In these cases the friction is determined by the adhesive contact between the involved surfaces that gives rise to intermittent sliding. For the diamond/Pt(111) and diamond/Pt-based metallic glass friction couples we measure COF = 0.002. There the relative motion between tip and sample surface did not exhibit any stick slip. The results are discussed on the basis of Pt-silicides formation and solid solution alloying between tip and sample surfaces.