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Nanocrystalline diamond thin films deposited from C60 monoenergetic fullerene ion beam.
Pukha, V E,Stetsenko, A N,Dub, S N,Lee, J K American Scientific Publishers 2007 Journal of Nanoscience and Nanotechnology Vol.7 No.4
<P>Carbon films 250 division by 500 nm in thickness deposited on Si wafers from mass-selected flow of accelerated C60 ions with energies of 5.0 +/- 0.1 keV at temperatures of 300 K and 673 K are characterized by TEM and nanoindentation. On the TEM images of the films deposited at 673 K, nanocrystalline graphite with the typical grain size of -6 nm is observed. The films deposited at 300 K are transparent in visible light. TEM study of these films has revealed structural elements with lattice spacing close to that of diamond and the grain size of about 4 nm. Nanohardness and elastic modulus of the films prepared at a substrate temperature of 300 K were 23.1 +/- 0.2 GPa and 200 +/- 1 GPa, respectively. Possible mechanisms of the carbon films structure formation are suggested in the framework of a hydrodynamic shock wave model.</P>
Highly wear-resistant and biocompatible carbon nanocomposite coatings for dental implants
Penkov, O.V.,Pukha, V.E.,Starikova, S.L.,Khadem, M.,Starikov, V.V.,Maleev, M.V.,Kim, D.E. IPC Science and Technology Press 2016 Biomaterials Vol.102 No.-
<P>Diamond-like carbon coatings are increasingly used as wear-protective coatings for dental implants, artificial joints, etc. Despite their advantages, they may have several weak points such as high internal stress, poor adhesive properties or high sensitivity to ambient conditions. These weak points could be overcome in the case of a new carbon nanocomposite coating (CNC) deposited by using a C-60 ion beam on a Co/Cr alloy. The structure of the coatings was investigated by Raman and XPS spectroscopy. The wear resistance was assessed by using a reciprocating tribotester under the loads up to 0.4 N in both dry and wet sliding conditions. Biocompatibility of the dental implants was tested in vivo on rabbits. Biocompatibility, bioactivity and mechanical durability of the CNC deposited on a Co/Cr alloy were investigated and compared with those of bulk Co/Cr and Ti alloys. The wear resistance of the CNC was found to be 250-650 fold higher compared to the Co/Cr and Ti alloys. Also, the CNC demonstrated much better biological properties with respect to formation of new tissues and absence of negative morphological parameters such as necrosis and demineralization. Development of the CNC is expected to aid in significant improvement of lifetime and quality of implants for dental applications. (C) 2016 Elsevier Ltd. All rights reserved.</P>
Lee, S.H.,Pukha, V.E.,Vinogradov, V.E.,Kakati, N.,Jee, S.H.,Cho, S.B.,Yoon, Y.S. Pergamon Press ; Elsevier Science Ltd 2013 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.38 No.33
A nanocomposite-carbon layer is coated onto the surface of 316L stainless steel (SS316) using a beam of accelerated C<SUB>60</SUB> ions at low temperature. The coating is composed of textured graphite nanocrystals ranging in size from 1 to 2 nm, with the graphene plane normal to the coating plane; the nanocrystals are separated by amorphous carbon. This orientation of the graphene layer provides low film resistivity in the direction of the substrate normal. Corrosion resistance tests performed in aggressive anodic and cathodic environments of a polymer electrolyte membrane fuel cell (PEMFC) show that the nanocomposite-carbon coated SS316L exhibits better anticorrosion properties than does bare SS316L. The interfacial contact resistance (ICR) of the nanocomposite-carbon coated SS316L is 12 m@? cm<SUP>2</SUP>, which is similar to that of graphite at a compaction force of 150 N cm<SUP>-2</SUP> and lower than a target of ~20 m@? cm<SUP>2</SUP>. A low value of ICR is maintained even after corrosion tests in aggressive anodic and cathodic environments. The fabricated nanocomposite-carbon coated SS316L exhibits excellent corrosion resistance and low interfacial contact resistance under simulated PEMFC bipolar plate conditions.
Carbon anode thin films for lithium batteries
남상철,이재명,Volodymyr E. Pukha,서현욱,김영독,이혜진 한국물리학회 2014 Current Applied Physics Vol.14 No.8
This paper describes a simple method to create carbon anode films for potential applications to the research field of lithium batteries. Carbon films were prepared using DC magneton sputtering with postannealing process in the range from room temperature (RT) to 700 C. Half cells assembled with lithium foils as the counter electrode and 1 M LiPF6 in EC:DMC (1:1 v/v) electrolytic solution was used to evaluate the discharging capacity of prepared anode thin films. We showed that carbon film deposited at RT can be more suitable for an anode material than that of higher temperature annealed films above 400 C. A variety of analysis methods including X-ray diffraction spectrometry (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were utilized to evaluate the defect density of the films; for example, the more defects on the film were identified when the carbon film was treated at a low temperature such as RT. It is envisioned that DC magnetron-sputtering with optimized process conditions can be useful for fabricating carbon based film anodes.
Self-Healing Phenomenon and Dynamic Hardness of C<sub>60</sub>-Based Nanocomposite Coatings
Penkov, Oleksiy V.,Pukha, Volodymyr E.,Devizenko, Alexander Yu.,Kim, Hae-Jin,Kim, Dae-Eun American Chemical Society 2014 NANO LETTERS Vol.14 No.5
<P>The phenomenon of surface self-healing in C<SUB>60</SUB>-based polymer coatings deposited by ion-beam assisted physical vapor deposition was investigated. Nanoindentation of the coatings led to the formation of a protrusion rather than an indent. This protrusion was accompanied by an abnormal shape of the force–distance curve, where the unloading curve lies above the loading curve due to an additional force applied in pulling the indenter out of the media. The coatings exhibited a nanocomposite structure that was strongly affected by the ratio of C<SUB>60</SUB> ion and C<SUB>60</SUB> molecular beam intensities during deposition. The coatings also demonstrated the dynamic hardness effect, where the effective value of the hardness depends significantly on the indentation speed.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-5/nl500321g/production/images/medium/nl-2014-00321g_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl500321g'>ACS Electronic Supporting Info</A></P>
Khadem, M.,Penkov, O.V.,Pukha, V.E.,Maleyev, M.V.,Kim, D.E. Pergamon Press ; Elsevier Science Ltd 2014 Carbon Vol.80 No.-
The wear resistance and optical properties of ultra-thin diamond-like carbon (DLC) coatings deposited on glass substrates at room temperature were investigated. The coatings were deposited using a C<SUB>60</SUB> ion beam. A sequence of surface treatments including ion-beam etching, molecular-beam deposition and ion-beam deposition were used for production of ultra-thin DLC coatings with a nano-patterned surface. The goal of the surface nano-patterning was to improve the wear resistance of the DLC coatings while maintaining a low thickness to obtain a high optical transparency. The experimental results demonstrated the excellent ability of the ultra-thin DLC coatings to improve the wear resistance of the glass substrates. A comparison between the wear rate for the DLC coating with nano-patterns and that of a more smooth coating revealed that the nano-patterned surface shows a 39% higher wear resistance. Furthermore, the coatings demonstrated a high transparency (94-97%) in the visible-light wavelength range.
Carbon anode thin films for lithium batteries
Nam, S.C.,Lee, J.M.,Pukha, V.E.,Seo, H.O.,Kim, Y.D.,Lee, H.J. Elsevier 2014 Current Applied Physics Vol.14 No.8
This paper describes a simple method to create carbon anode films for potential applications to the research field of lithium batteries. Carbon films were prepared using DC magneton sputtering with post-annealing process in the range from room temperature (RT) to 700 <SUP>o</SUP>C. Half cells assembled with lithium foils as the counter electrode and 1 M LiPF<SUB>6</SUB> in EC:DMC (1:1 v/v) electrolytic solution was used to evaluate the discharging capacity of prepared anode thin films. We showed that carbon film deposited at RT can be more suitable for an anode material than that of higher temperature annealed films above 400 <SUP>o</SUP>C. A variety of analysis methods including X-ray diffraction spectrometry (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were utilized to evaluate the defect density of the films; for example, the more defects on the film were identified when the carbon film was treated at a low temperature such as RT. It is envisioned that DC magnetron-sputtering with optimized process conditions can be useful for fabricating carbon based film anodes.