In the present work, it is shown that the friction stress of ethylene glycol can decrease by an order of magnitude to achieve superlubricity if there are hydrogen ions attached on the friction surfaces. An ultra-low friction coefficient (μ = 0.004) of ethylene glycol between Si3N4 and SiO2 can be obtained with the effect of hydrogen ions. Experimental result indicates that the hydrogen ions ads...

Influence of initial surface roughness on friction and wear processes under fretting conditions was investigated experimentally. Rough surfaces (Ra=0.15-2.52 μm) were prepared on two materials: carbon alloy (AISI 1034) and titanium alloy (Ti-6Al-4V). Strong influence of initial surface roughness on friction and wear processes is reported for both tested materials. Lower coefficient of friction ...

The resistance against rolling of a rigid cylinder on a flat viscous surface is investigated. We found that the rolling-friction coefficient reveals strongly non-linear dependence on the cylinder’s velocity. For low velocity the rolling-friction coefficient rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity according t...

N. Ratković, Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia. R. Nikolić, Faculty of Civil Engineering, University of Žilina, Žilina, Slovakia. I. Samardžić, University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Croatia. Fundamental principles of friction welding of dissimilar steels (high speed and tempering steel) from the aspect of metallurgical and che...

some physical properties such as geometrical, gravimetrical, frictional and aerodynamic features of seeds of desi chickpea and its splits were studied at a moisture content of 8.2 and 9.0% w., respectively from north-western of iran. geometrical and gravimetrical properties including the average length, width, thickness, the geometric mean of diameter, sphericity, 1000-seed weight, unit weight,...