M. Haršáni, N. Ghafoor, K. Calamba, P. Zacková, M. Sahul, T. Vopát, L. Satrapinskyy, M. Čaplovičová, Ľ. Čaplovič,
Thin Solid Films, Volume 650, 2018, Pages 11-19
doi.org/10.1016/j.tsf.2018.02.006
M. Haršáni, N. Ghafoor, K. Calamba, P. Zacková, M. Sahul, T. Vopát, L. Satrapinskyy, M. Čaplovičová, Ľ. Čaplovič,
Thin Solid Films, Volume 650, 2018, Pages 11-19
doi.org/10.1016/j.tsf.2018.02.006
M. Haršáni, N. Ghafoor, K. Calamba, P. Zacková, M. Sahul, T. Vopát, L. Satrapinskyy, M. Čaplovičová, Ľ. Čaplovič
In Thin Solid Films. Vol. 650, (2018)
https://doi.org/10.1016/j.tsf.2018.02.006
A series of Al-Cr-Si-N hard coatings were deposited on WC-Co substrates with a negative substrate bias voltage ranging from −50 to −200 V using cathodic arc evaporation system. A Rockwell-C adhesion test demonstrated that excellent adhesion was observed at lower bias voltages of −50 V and −80 V, while further increases in bias voltage up to −200 V led to severe delamination and worsening of the overall adhesion strength. X-ray diffraction and transmission electron microscopy analysis revealed a single phase cubic B1-structure identified as an AlCrN solid solution with a nanocomposite microstructure where cubic AlCrN nanocrystals were embedded in a thin continuous amorphous SiNx matrix. Coatings exhibited a 002-texture evolution that was more pronounced at higher bias voltages (≥−120 V). Stress-induced cracks were observed inside the coatings at high bias voltages (≥−150 V), which resulted in stress relaxation and a decline in the overall residual stresses.
BODIK, Michal – ŠIFFALOVIČ, Peter – NÁDAŽDY, Peter – BENKOVIČOVÁ, Monika – MARKOVIČ, Zoran – CHLPÍK, Juraj – CIRÁK, Július – KOTLÁR, Mário – MICUŠÍK, M. – JERGEL, Matej – MAJKOVÁ, Eva
In Diamond and Related Materials. Vol. 83, (2018)
https://doi.org/10.1016/j.diamond.2018.02.011
In this work, we present a study of the Langmuir film formation composed of hydrophobic carbon quantum dots (hCQDs). We studied the kinetics of hCQDs pyrolysis and optimized the reaction time for maximum photoluminescence. The resulting hCQDs were analyzed by transmission electron microscopy, X-ray photoemission spectroscopy and grazing-incidence X-ray diffraction. The process of monolayer formation was studied by monitoring surface pressure, surface potential, elastic modulus and Brewster angle microscopy in real time under continuous compression conditions. The monolayer transferred onto a silicon wafer was examined on the nano- and micro-scales by means of atomic force microscopy and confocal fluorescence microscopy, respectively.
MOTOLA, Martin – SATRAPINSKYY, L – ČAPLOVIČOVÁ, Mária – ROCH, Tomáš – GREGOR, Maroš – GRANČIČ, B. – GREGUŠ, J. – ČAPLOVIČ, Ľubomír – PLESCH, Gustav
In Applied Surface Science. Vol. 434, 15 March 2018 (2018)
https://doi.org/10.1016/j.apsusc.2017.11.253
TiO2 nanotube (TiNT) arrays were grown on silicon substrate via electrochemical anodization of titanium films sputtered by magnetron. To improve the photocatalytic activity of arrays annealed in air (o-TiNT), doping of o-TiNT with vanadium was performed (o-V/TiNT). These non-doped and doped TiNT arrays were also hydrogenated in H2/Ar atmosphere to r-TiNT and r-V/TiNT samples, respectively. Investigation of composition and morphology by X-ray diffraction (XRD), electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS) showed the presence of well-ordered arrays of anatase nanotubes with average diameter and length of 100 nm and 1.3 μm, respectively. In both oxidized and reduced V-doped samples, vanadium is partly dissolved in the structure of anatase and partly deposited in form of oxide on the nanotube surface. Vanadium-doped and reduced samples exhibited higher rates in the photodegradation of organic dyes (compared to non-modified o-TiNT sample) and this is caused by limitation of electron-hole recombination rates and by shift of the energy gap into visible region. The photocatalytic activity was measured under UV, sunlight and visible irradiation, and the corresponding efficiency increased in the order (o-TiNT) < (r-TiNT) < (o-V/TiNT) < (r-V/TiNT). Under visible light, only r-TiNT and r-V/TiNT showed significant photocatalytic activity.