Showing 4 results for Multilayer
S. M. M. Shafiei, M. Divandari, S. M. A. Boutorabi, Naghizadeh,
Volume 12, Issue 2 (6-2015)
Abstract
In this work, TiN/TiCN & PN/TiCN multilayer films were deposited by plasma- assisted chemical vapour
deposition (PACVD). Plasma nitriding (PN) and TiN intermediate layer prior to coating leads to appropriate hardness
gradient and it can greatly improve the mechanical properties of the coating. The composition, crystalline structure
and phase of the films were investigated by X-ray diffraction. Atomic force microscopy and scanning electron
microscopy were employed to observe the morphology and structure of the films. The TiCN layer exhibited a columnar
structure. The adhesion force between the film and the tool steel substrate was 30.8 MPa for TiN/TiCN and 25.4 MPa
for PN/TiCN film determined by pull off tests. The hardness of TiN/TiCN film was 12.75 GPa while it was 5.4 GPa for
PN/TiCN film, respectively. The improvement of the adhesion in TiN/TiCN was attributed to a less gradient hardness
configuration. In addition, the mean friction coefficients of the films were about 0.2 for TiN/TiCN and 0.3 for PN/TiCN
film determined by nanoindentation tests.
Parviz Parviz Mohamadian Samim, Arash Fattah-Alhosseini, Hassan Elmkhah, Omid Imantalab,
Volume 19, Issue 1 (3-2022)
Abstract
In this study, CrN/ZrN multilayer nanostructured coatings with different bilayers (10, 20, and 30) were created by the cathodic arc evaporation. The electrochemical behavior of samples was evaluated by polarization and impedance spectroscopy tests in the Ringer medium and the pin on disk test was used to investigate the tribological behavior of the samples. The results of measurements showed that the electrochemical and tribological behavior of the coatings depends on the number of bilayers and by rising the number of bilayers, the coating shows higher corrosion resistance and better tribological performance. Field emission scanning electron microscopy (FE-SEM) images of the specimens after exposure to the corrosion medium showed that the number of surface cavities were formed by the coating that had the highest number of bilayers comparing with other coatings were quite fewer in number and smaller in diameter. The results of the pin on disk test showed that by increasing the number of bilayers from 10 to 30, the coefficient of friction and wear rate decreased and the 30L coating showed better wear resistance.
Erfan Lotfi-Khojasteh, Hassan Elmkhah, Meisam Nouri, Omid Imantalab, Arash Fattah-Alhosseini,
Volume 19, Issue 4 (12-2022)
Abstract
This paper aims to study the tribological and electrochemical properties of the CrN/AlCrN nano-layer deposited on H13 tool steel. Arc physical technique was employed to deposit multilayer coating. X-ray diffraction technique, thermionic and field emission scanning electron microscopy and energy dispersive spectroscopy have been used to determine the characteristics of the samples. To study the samples' wear behavior, coating adhesion, and surface hardness, reciprocating wear test, Rockwell-C test, and microhardness Vickers tester were employed, respectively. The measured values of the coefficient of friction and the calculated wear rates showed that the CrN/AlCrN multilayer coating has a much higher wear resistance than the uncoated sample. The coefficient of the friction of the coated sample was 0.53 and that of the uncoated sample was 0.78. Moreover, the wear rate of the coated H13 steel was about 127 times lower than the bare H13 steel sample. The results obtained from electrochemical impedance spectroscopy and polarization tests demonstrated that the corrosion current density of the H13 steel sample was 8 μA/cm2 and that of the CrN/AlCrN multilayer-coated sample was 3 μA/cm2. In addition, the polarization resistance of the treated and the substrate specimens was estimated at 4.2 and 2.7 kΩ.cm2, respectively.
Mozhgan Hirbodjavan, Arash Fattah-Alhosseini, Hassan Elmkhah, Omid Imantalab,
Volume 19, Issue 4 (12-2022)
Abstract
The principal goal of this research is to produce a CrN/Cu multilayer coating and a CrN single-layer
coating and also compare their electrochemical and antibacterial behavior. In this investigation, the coatings were
applied to the stainless steel substrate by cathodic arc evaporation a sub-division of physical vapor deposition
(CAE-PVD). The present phases were characterized and the thickness of the coatings was measured using X-ray
diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), respectively. Rockwell-C tester was
used to evaluate the adhesion quality. Also, to evaluate the mechanical properties of the coatings such as modulus
of elasticity and hardness, a nanoindentation test was used and the indentation effect and coating topography were
evaluated using atomic force microscopy (AFM). Studying the electrochemical behavior of the coatings was done
using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests in Ringer's
solution. The results of EIS tests showed that the CrN coating had higher polarization resistance in comparison to
the CrN/Cu coating and an increasing trend of polarization resistance related to both coatings was identified by
rising the time of immersion. Also, using the PDP curves, the CrN and CrN/Cu coating current densities were
estimated at 1.835×10-8 and 2.088×10-8, respectively. The antibacterial activity of CrN and CrN/Cu coatings was
evaluated by the spot-inoculation method. The results of the antibacterial test indicated that compared to CrN
coating, CrN/Cu coating had a better impact on the control of the bacteria growth.
