Browsing by Subject "Friction coefficients"

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    Nanocomposite glass coatings containing hexagonal boron nitride nanoparticles
    (Pergamon Press, 2016) Çamurlu, H. E.; Akarsu, E.; Arslan, O.; Mathur, S.
    Glass coatings composed of SiO2-K2O-Li2O, containing non-modified and fluorosilane modified hexagonal boron nitride (hBN) nanoparticles, were prepared on stainless steel plates through sol-gel spin-coating method. Coatings were examined by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), atomic force microscopy (AFM) and thermo-gravimetric analysis (TGA). 1.3-2.5 μm thick uniform coatings were obtained after curing at 500 °C for 1 h. The coatings adhered well to the steel substrates. It was determined by salt spray tests that the coatings enhance corrosion resistance. The aim of hydrophobic fluorosilane modification of hBN nanoparticles was to enrich hBN quantity on the top surface of the coatings. Coatings containing fluorosilane modified hBN nanoparticles presented slightly lower friction coefficient values than the other coatings.
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    Nanoscale tribology of graphene grown by chemical vapor deposition and transferred onto silicon oxide substrates
    (Cambridge University Press, 2016) Demirbaş, T.; Baykara, M. Z.
    We present a comprehensive nanoscale tribological characterization of single-layer graphene grown by chemical vapor deposition (CVD) and transferred onto silicon oxide (SiO2) substrates. Specifically, the nanotribological properties of graphene samples are studied via atomic force microscopy (AFM) under ambient conditions using calibrated probes, by measuring the evolution of friction force with increasing normal load. The effect of using different probes and post-transfer cleaning procedures on frictional behavior is evaluated. A new method of quantifying lubrication performance based on measured friction coefficient ratios of graphene and SiO2 is introduced. A comparison of lubrication properties with mechanically-exfoliated graphene is performed. Results indicate that CVD-grown graphene constitutes a very good solid lubricant on SiO2, reducing friction coefficients by ∼ 90% for all investigated samples. Finally, the effect of wrinkles associated with CVD-grown graphene on measured friction values is quantitatively analyzed, with results revealing a substantial increase in friction on these structural defects.