TY - JOUR A1 - Fahrbach, M. A1 - Friedrich, Sebastian A1 - Behle, H. A1 - Xu, Min A1 - Cappella, Brunero A1 - Brand, U. A1 - Peiner, E. T1 - Customized piezoresistive microprobes for combined imaging of topography and mechanical properties JF - Measurement: Sensors N2 - Customized piezoresistive cantilever microprobes with a deflection range of 120 μm and silicon tips of 100 μm height were operated in a Cypher AFM showing their functionality for measuring topography together with stiffness, adhesion, and viscoelastic properties of thin films. KW - Cantilever microprobe KW - Piezoresistive KW - Atomic force microscopy KW - Force-distance curves KW - Contact resonance KW - Lubricants PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524225 DO - https://doi.org/10.1016/j.measen.2021.100042 VL - 15 SP - 100042 PB - Elsevier Ltd. AN - OPUS4-52422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Sebastian A1 - Cappella, Brunero T1 - Study of micro- and nanoscale wetting properties of lubricants using AFM force-distance curves JF - Tribology letters N2 - Atomic force microscopy (AFM) plays an important role as a multifuntional tool in nanotribology.In the present work it was shown that the main features of force-distance curves on different lubricants have been characterized and the underlying phenomena could be explained. KW - Lubricants KW - Atomic force microscopy KW - Force-distance curves PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504631 DO - https://doi.org/10.1007/s11249-020-1275-3 SN - 1573-2711 VL - 68 IS - 1 SP - 1 EP - 12 PB - Springer CY - Cham AN - OPUS4-50463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gili, F. A1 - Igartua, A. A1 - Luther, R. A1 - Woydt, Mathias T1 - The impact of biofuels on engine oil performance JF - Lubrication science N2 - The dilution of biogenic fuels into lubricating engine oils often leads to a shortening of the recommended oil drains (between 30% and 60%) and an increase in wear. The large number of overlapping and influencing factors, of which dilution and polymerization of fuel components in the engine oil are emphasised, makes it difficult to find a uniform solution to prevent failures in the various applications. Insofar single solutions for the different types of biofuels are needed. The contribution of base oil chemistry and additives as well as triboactive materials is featured to deal with the adverse effects of biofuels. In the frame of the European Commission (EC)-funded project 'cleanengine', tentative engine oils based on esters with a content of renewables and polyglycols are formulated to increase the lubricant's tolerance in engines fuelled with biofuel-based blends, with the aim of ensuring required lubricating and wear protection performance while keeping oil drain intervals unchanged. The present paper focuses on four-stroke diesel applications, fuelled by biodiesel (fatty acid methyl ester — FAME) as well as by rapeseed oil and Jatropha oil (pure vegetable oils, triglycerides), together with relevant blends of those biofuels and conventional diesel fuel. This paper screens the functional profile (in particular rheological, toxicological, bio-compatibility, tribological and biofuels affinity) of lube families with respect to biofuel contamination. Moreover, this is followed by the contributions of piston ring and liner materials as well as thin film coatings. KW - Lubricants KW - Engine oil KW - Additives KW - Biofuel KW - Ester KW - Polyglycol KW - Thin film coatings KW - Slip-rolling KW - DLC KW - Dilution KW - FAME KW - Jatropha KW - Rapeseed KW - Stem valve KW - Piston ring PY - 2011 DO - https://doi.org/10.1002/ls.158 SN - 0954-0075 SN - 1557-6833 VL - 23 IS - 7 SP - 313 EP - 330 PB - Leaf Coppin Publ. Ltd. CY - Deal AN - OPUS4-24831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rawat, S. S. A1 - Harsha, A. P. A1 - Khatri, O. P. A1 - Wäsche, Rolf T1 - Pristine, reduced, and alkylated graphene oxide as additives to paraffin grease for enhancement of tribological properties JF - Journal of Tribology N2 - Pristine, reduced, and alkylated graphene oxides are applied as lubricating additives in paraffin grease. It has revealed that their crystalline structure governs the tribological properties of grease for steel tribo-pair. The microstructural analyses of grease samples showed that a loose fiber network of soap in the presence of graphene-based additive allows their facile release for efficient lubrication. The surface analyses based on the microscopic and elemental mapping show the development of a graphene-derived protective film on the worn scars, which protected the tribo-surfaces and subsided the wear. The reduced graphene oxide (rGO) with the interlamellar distance of 0.35 nm in the (002) plane provided minimum resistance to shear and exhibited maximum reduction in coefficient of friction (COF) for the paraffin grease. The presence of oxygen functionalities in the basal of pristine and alkylated graphene oxide (GO) compromised the interlamellar shearing under tribo-stress; consequently, higher COF than that of rGO. KW - Coefficient of friction KW - Graphene oxide KW - Grease KW - Nanoadditive KW - Tribo-film KW - Wear KW - Boundary lubrication KW - Grease lubrication KW - Lubricant additives KW - Lubricants PY - 2021 DO - https://doi.org/10.1115/1.4047952 VL - 143 IS - 2 SP - 021903-1 EP - 021903-11 PB - ASME AN - OPUS4-51170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, R. A1 - Klingenberg, G. A1 - Woydt, Mathias T1 - Thermophysical and viscosimetric properties of environmentally acceptable lubricants JF - Industrial Lubrication and Tribology KW - Lubricants KW - Oils KW - Internal combustion engines KW - Mechanical properties of materials KW - Chemical properties of materials PY - 2006 SN - 0036-8792 VL - 58 IS - 4 SP - 210 EP - 224 PB - Peterson CY - Droitwich, Worcs. AN - OPUS4-15747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Criqui, B. A1 - Desplanches, G. A1 - Linneman, T. T1 - Zero wear concept using bionotox and polymerfree engine oils with triboactive materials JF - Industrial Lubrication and Tribology N2 - The purpose of this paper is to underline the future need for OEMs to receive lowSAP, polymer- and metal-free engine oils with high-viscosity indices and to illuminate for other OEMs the technical feasibility for application of alternative engine oils based on esters or blends of hydrocarbons with esters or polyglycols. Design/methodology/approach – The strategic goal depends technically on the use of intrinsic properties of alternative base fluids, thus substituing some additives, like anti-wear, extreme pressure and viscosity index improvers. The prone wear resistance of novel triboactive/-reactive materials enables higher portions of mixed/boundary lubrication generated by oils with a lower viscosity. Findings – Overall, the different bionotox and low-ash prototype engine oils with reduced additive contents displayed isoperformance regarding the tribological behaviour against cast iron and triboreactive materials. APS-Tin-2Cr2O2n-1 displayed an overall wear resistance comparable with grey cast iron with high-carbon content and liner wear reduction of one order of magnitude when mated with Mo-based rings. Both tests confirmed the potential for substituing molybdenum-based rings by APS-Tin-2Cr2O2n-1. The most significant reduction in “system wear” down to “zero wear” was demonstrated by mating the APS-Tin-2Cr2O2n-1 coated piston rings with smooth machined HVOF-(Ti,Mo)(C,N) liner coatings. Research limitations/implications – As lubricants are today not part of the core business of automotive OEMs, the next steps have to be proposed by the petrochemical suppliers. It is recalled here that some OEMs in their history developed and produced lubricants. Practical implications – The customer will appreciate any increase in longevity resulting in reduced maintenance. The OEM now owns, under increased solicitations, now a future-oriented tool box in order to respond to environmental and CAFÉ demands with reasonable cost management. Originality/value – This OEM report displays the complete methodology in order to adopt alternative engine oils in existing engine architectures. KW - Oils KW - Additives KW - Lubricants PY - 2008 DO - https://doi.org/10.1108/00368790810839891 SN - 0036-8792 VL - 60 IS - 1 SP - 14 EP - 23 PB - Peterson CY - Droitwich, Worcs. AN - OPUS4-17357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -