Ingenieurwissenschaften und zugeordnete Tätigkeiten
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The frictional response of molybdenum bis(C11-14 branched and linear alkyl) carbamodithioate oxo thioxo complex (Mo-dttc) versus bismuth dimethyldithiocarbamate (Bi-dtc) and bismuth dodecylbenzene Sulfonate (Bi-ddbsa) slip-rolling under mixed/boundary lubrication (T=120°C, n=10 millions of cycles, P0max=2.25 GPa) in PAO-based formulation against three different steel alloys were compared.
The effects of UV radiation and humidity condition on the frictional properties of TPU materials are presented in this paper.
Photooxidative degradation of polymer leads to deterioration of physical and mechanical properties, which affect its tribological behavior significantly.
Unfilled TPUs lose their anti-slip properties.
The effects of UV radiation and humidity condition on the frictional properties of TPU materials are presented in this paper.
Photooxidative degradation of polymer leads to deterioration of physical and mechanical properties, which affect its tribological behavior significantly.
Unfilled TPUs lose their anti-slip properties.
Titanium nitride (TiN) was coated on different substrate materials, namely pure titanium (Ti), titanium alloy (Ti6Al4V) and steel (100Cr6), generating 2.5 μm thick TiN layers. Using femtosecond laser pulses (30 fs, 790 nm, 1 kHz pulse repetition rate), large surface areas (5 mm × 5 mm) of laser-induced periodic surface structures (LIPSS) with sub-wavelength periods ranging between 470 nm and 600 nm were generated and characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). In tribological tests, coefficients of friction (COF) of the nanostructured surfaces were determined under reciprocating sliding conditions (1 Hz, 1.0 N normal load) against a 10-mm diameter ball of hardened 100Cr6 steel during 1000 cycles using two different lubricants, namely paraffin oil and engine oil. It turned out that the substrate material, the laser fluence and the lubricant are crucial for the tribological performance. However, friction and wear could not be significantly reduced by LIPSS on TiN layers in comparison to unstructured TiN surfaces. Finally, the resulting wear tracks on the nanostructured surfaces were investigated with respect to their morphology (OM, SEM), depth (WLIM) and chemical composition by energy dispersive X-ray spectroscopy (EDX) and, on one hand, compared with each other, on the other hand, with non-structured TiN surfaces.
The differences between the binary phase diagrams W-C and Nb-C illuminate several parameters for tailoring the properties of NbC. In the region of homogeneity of NbCx, with Nb4C3 and Nb6C5 other Niobium carbide phases occur. Properties, like micro-hardness, hot hardness, sliding wear, elastic modules and toughness can be tailored by the C/Nb Ratio, secondary carbides and the type of binder. Supporting results from different grades with varying C/Nb ratio or binder types will be illuminated. Thus, the NbC system offers to producers a wider parameter window, than WC.