Browsing by Author "Parfenov, E. V."

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Effect of frequency on plasma electrolytic oxidation of zirconium in pulsed unipolar mode
(IOP Conf. Series: Materials Science and Engineering, 2019) Parfenov, E. V.; Mukaeva, V. R.; Farrakhov, R. G.; Saikiran, A.; Hariprasad, S.; Manoj, P.; Lokesh, E.; Rameshbabu, N.
Using the method of in situ impedance spectroscopy, an optimization of plasma electrolytic oxidation (PEO) was performed, and the influence of the pulse frequency was evaluated for the coating of Zr-1Nb alloy. It was shown that the in situ impedance modulus decreased with increasing the pulse frequency in a pulsed unipolar mode. Also, the protective properties of the coating improved with frequency; this was attributed to the increase in the uniform distribution of the microdischarges over the sample surface. As a result, the optimal frequency range of PEO was justified based on the impedance spectroscopy studies.
Superior properties and behaviour of coatings produced on nanostructured titanium by PEO coupled with the EPD process
(Surface Topography: Metrology and Properties, 2022-02-18) Lokeshkumar, E.; Saikiran, A.; Ravisankar, B.; Krishna, Rama.; Parfenova, L. V.; Parfenov, E. V.; Valiev. R. Z.; Rameshbabu, N.
Surface modification of commercially pure Grade 4 coarse-grained titanium (CG-Ti) and nano-grained titanium (n-Ti) by plasma electrolytic oxidation (PEO) and plasma electrolytic oxidation conjugated with electrophoretic deposition (PEO-EPD) processes is reported in the present study. Two different coatings were developed on each CG-Ti and n-Ti in phosphate-based electrolytes without and with the incorporation of hydroxyapatite (HA) nanoparticles. The phase composition, morphology (surface and cross-sectional), corrosion resistance, surface roughness, and scratch-resistance of the fabricated coatings were thoroughly studied and analysed. The L-929 fibroblast cells were used for assessing the in-vitro cell viability. The L-929 cells cultured on PEO-EPD treated CG-Ti, and n-Ti samples exhibited higher cell growth than PEO treated CG-Ti and n-Ti samples. Among all the PEO and PEO-EPD treated samples, the PEO-EPD treated n-Ti sample showed significantly better corrosion resistance (icorr = 8.85 × 10−7 mA cm−2 ), lower contact angle (40°), and good adhesion strength (Lc = 29 N), demonstrating the importance of the nanostructuring of the titanium substrate for the properties of the coating. The origin of the discovered enhancement in the properties of the modified PEO coating produced on nanostructured titanium was examined and discussed. After soaking in SBF for 14 days, the PEO-EPD treated sample is wholly covered with apatite layer indicating its good bioactivity
Surface modification of CP-Ti metallic implant material by plasma electrolytic oxidation
(IOP Conf. Series: Materials Science and Engineering, 2019) Rameshbabu, N.; Ravisankar, B.; Saikiran, A.; Parfenov, E. V.; Valiev, R. Z.
Plasma electrolytic oxidation (PEO) is a relatively new and environmentally friendly process for development of thick and adherent oxide coatings on conventional and nanostructured metallic implant materials. The PEO process involves anodic oxidation of metals or alloys in aqueous solutions at voltages higher than the breakdown voltage of the oxides present on its surfaces. Currently, the PEO process is gaining increased attention as a novel technique for the fabrication of corrosion resistant, bioactive and functionally modulated composite coatings on commercial pure titanium (Cp-Ti) and Ti based alloys for orthopedic and dental applications. The PEO process coupled with the electrophoretic deposition (EPD) technique is used for the fabrication of TiO2/hydroxyapatite (HA) composite coating on a Cp-Ti implant material in a single step. This paper briefly reviews the properties of the coatings produced on Cp-Ti by PEO and PEO coupled EPD processes.