TY - JOUR A1 - Reichelt, Manuel A1 - Cappella, Brunero T1 - Micro- and nanowear of self-mated steel generated and studied with an AFM at the single asperity level JF - Frontiers in mechanical engineering N2 - We show for the first time tribotests performed with self-mated 100Cr6 steel, taking advantage of an AFM, employed as a tribometer for the tribotests as well as for the inspection of wear of both tribopartners. Emphasis is put on the morphology of the scars, on wear particles, and on wear of the “colloidal” particles glued on the AFM cantilever. Measurements demonstrate the possibility of characterizing single asperity events leading to very small wear. We highlight several phenomena, which are elementary key constituents of tribological processes. Such phenomena, probably occurring also at the macroscale, can be detected, identified, and characterized with high spatial and time resolution only at the nanoscale, thus giving insight into conditions and causes of their emergence. KW - Nanowear KW - Atomic force microscope KW - 100Cr6 (AISI 52100) steel KW - Wear particles KW - Single asperity contact KW - Particle transfer KW - Zero wear PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531389 DO - https://doi.org/10.3389/fmech.2021.722434 SN - 2297-3079 VL - 7 SP - 1 EP - 16 PB - Frontiers Media CY - Lausanne AN - OPUS4-53138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Stark, Wolfgang T1 - Adhesion of amorphous polymers as a function of temperature probed with AFM force-distance curves JF - Journal of colloid and interface science N2 - Force–displacement curves have been obtained with a commercial atomic force microscope at different temperatures and probe rates on a thick film of poly(n-butyl methacrylate) and on two films of polystyrene with different molecular weight. In a previous publication [B. Cappella, S.K. Kaliappan, H. Sturm, Macromolecules 38 (2005)1874] the analysis of force–displacement curves has been focused on the stiffness and on the Young's modulus of the samples. In the present publication we consider the temperature dependence of the work of adhesion. We have obtained master curves of the work of adhesion at fixed maximum loads and, by comparing the results of the two analysis, we show that the work of adhesion follows the Williams–Landel–Ferry equation with the same coefficients previously found for the Young's modulus. Furthermore, we show that the temperature dependence of the work of adhesion of the polymers is a consequence of the temperature dependence of the tip–sample contact area and in the end of the temperature dependence of the stiffness and of the elastic–plastic properties of the samples. KW - Atomic force microscope KW - Force-distance curves KW - Indentation KW - Elastic-plastic properties KW - Adhesion KW - Time-temperature superposition principle KW - Glass transition temperature PY - 2005 DO - https://doi.org/10.1016/j.jcis.2005.09.043 SN - 0021-9797 SN - 1095-7103 SP - 1 EP - 8(?) PB - Elsevier CY - Orlando, Fla. AN - OPUS4-11187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Butt, H.-J. A1 - Cappella, Brunero A1 - Kappl, M. T1 - Force measurements with the atomic force microscope - Technique, interpretation and applications JF - Surface science reports N2 - The atomic force microscope (AFM) is not only a tool to image the topography of solid surfaces at high resolution. It can also be used to measure force-versus-distance curves. Such curves, briefly called force curves, provide valuable information on local material properties such as elasticity, hardness, Hamaker constant, adhesion and surface charge densities. For this reason the measurement of force curves has become essential in different fields of research such as surface science, materials engineering, and biology. Another application is the analysis of surface forces per se. Some of the most fundamental questions in colloid and surface science can be addressed directly with the AFM: What are the interactions between particles in a liquid? How can a dispersion be stabilized? How do surfaces in general and particles in particular adhere to each other? Particles and surfaces interactions have major implications for friction and lubrication. Force measurements on single molecules involving the rupture of single chemical bonds and the stretching of polymer chains have almost become routine. The structure and properties of confined liquids can be addressed since force measurements provide information on the energy of a confined liquid film. After the review of Cappella [B. Cappella, G. Dietler, Surf. Sci. Rep. 34 (1999) 1–104] 6 years of intense development have occurred. In 1999, the AFM was used only by experts to do force measurements. Now, force curves are used by many AFM researchers to characterize materials and single molecules. The technique and our understanding of surface forces has reached a new level of maturity. In this review we describe the technique of AFM force measurements. Important experimental issues such as the determination of the spring constant and of the tip radius are discussed. Current state of the art in analyzing force curves obtained under different conditions is presented. Possibilities, perspectives but also open questions and limitations are discussed. KW - AFM KW - Force curves KW - Surface forces KW - Atomic force microscope PY - 2005 DO - https://doi.org/10.1016/j.surfrep.2005.08.003 SN - 0167-5729 VL - 59 IS - 1-6 SP - 1 EP - 152 PB - North-Holland CY - Amsterdam AN - OPUS4-11181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Santner, Erich A1 - Spaltmann, Dirk T1 - Adhesion of cleaned nanoscopic metal contacts JF - TriboTest KW - Nanoscopic metal contacts KW - Adhesion KW - Friction KW - Atomic force microscope KW - AFM KW - Theoretical models PY - 2003 SN - 1354-4063 SN - 1557-685X VL - 9-4 SP - 333 EP - 344 PB - Coppin CY - Deal AN - OPUS4-2620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -