The wear resistance of diamond-like a-C:H coatings deposited onto substrates of R6M5 steel through intermediate Ti-C layers with a titanium concentration of 10 to 90% is studied. The a-C:H coatings with a thickness of 1500 nm are fabricated via the destruction of acetylene in the plasma of a non-self-maintained discharge generated by an electron beam in a mixture of acetylene and argon. Intermediate Ti–C layers with a thickness of ~100 nm are fabricated by the arc sputtering of a titanium alloy (VT-1-0) cathode in the acetylene-argon plasma of a non-self-maintained discharge. The partial pressure of argon is kept constant (0.03 Pa), and that of acetylene varied from 0.01 to 1 Pa. An increase in the acetylene pressure is accompanied by a decrease in the titanium concentration in Ti–C. Testing the coatings in a jet of silicon-carbide particles with an average size of 100 microns, incident normally to the surface at a speed of 10 m/s, shows that the composition and structure of the intermediate layers have a significant effect on the stability of a-C:H coatings. An increase in the carbon content in the Ti–C structure leads to a decrease in the size of crystal inclusions in the amorphous matrix, increasing the probability of the formation of interphase boundaries that inhibit the movement and generation of dislocations (the source of crack origin), the advance of which destroys the hard coating. Amorphous carbon in Ti–C provides good interlayer adhesion. During the deposition of a-C:H on Ti–C, there is a cohesive bonding between the same phases (carbon) and adhesive bonding between different phases (carbon and titanium carbide).

The composition, structure and corrosion behaviour of CrxAly(SOC coatings fabricated by the arc discharge techniques using Cr-Al-Si and graphite cathodes were studied. X-ray photoelectron spectroscopy, X-ray energy-dispersive spectroscopy, nuclear reactions, and Rutherford backscattering methods were applied to determine composition of the coating, X-ray diffraction and transmission electron microscopy - to investigate the structure of the coating. Corrosion tests were performed in an electrochemical cell in a 3.5%NaCl solution. Depletion of the cathode surface of chromium, screening of Cr+ by C+ in plasma, and selective etching of the coating upper layers are accompanied by a decrease of Cr/(Al +Si) ratio in the coatings compared to the cathode. The carbon content (C-C) in CrxAl(Si)(y)C, determined by XPS, EDS and NR, differs by several times. The C-C, measured by NR correlates with the results of Raman spectroscopy and confirms the existence of a continuous carbon matrix in CrxAly(Si)C. Cr is chemical bonded with carbon, silicon - with carbon and aluminum. The Al-Si system provides the structure feature of CrxAl(Si)(y)C: a network of aluminum intersects the amorphous matrix. The mechanical mismatch and weak bond between the Al structures and the amorphous matrix may be the reason for the formation of defects in the form of cracks and microchannels along the boundaries.

The wear-resistant coatings formed by the vacuum ion-plasma codeposition of titanium and carbon have been studied in this work. Single-layer and multilayer coatings with the systematically repeated [(Ti1 – xCx/a-C] pair are deposited onto P8M5 and 18KhN10T steel substrates. The highest erosion resistance is inherent in the multilayer [Ti0.2C0.8/a-C]40 coating with a layer thickness of 25 nm. The erosion wear rate of this coating is 1.6–1.8 times lower than the wear rate of the single-layer а-С and Ti0.2C0.8 coatings. The wear of [Ti0.2C0.8/a-C]40 occurs layer by layer without crumbling of individual square sections of the coating, thus increasing its service life. The interphase boundaries in the Ti0.2C0.8 composite layer, as well as the Ti1 ‒ xCx → а-С interface boundaries, serve as a barrier for the propagation of microcracks, decreasing the probability of macrocracking, which destroys the continuity of a coating.

There were investigated tribological properties of CrAlSiC coatings deposited by two techniques. In both techniques a plasma source of a cathode-arc discharge with Cr-Al-Si composite target served the source of Cr, Al, and Si atoms during coating deposition. A plasma source of a pulsed cathode-arc discharge with graphite cathode and a gas discharge device to generate a non-self-sustained discharge in argon-acetylene mixture have been used for generating carbon plasma in first and second techniques, correspondingly. First coating has a low coefficient of friction. Under frictional action, coating wears out uniformity without chipping. Second coating is less resistant to frictional action.

CrAlSiC films deposited under various conditions of carbon-plasma generation (PVD or PACVD) are investigated. A plasma source of cathodic-arc discharge with a Cr–Al–Si cathode and a source of pulsed cathodic-arc discharge with a graphite cathode are used for the deposition of a CrAlSiC(I) film. A plasma source of cathodic-arc discharge with a Cr–Al–Si cathode and a gas-discharge device for generating a non-self-sustaining discharge in an argon-acetylene mixture are applied for the deposition of a CrAlSiC(II) film. The sources work together in both processes. The film structure is investigated using electron microscopy and Raman spectroscopy. The hardness and elasticity modulus are determined by nanoindentation; the friction coefficient is tested with the reciprocating motion of a steel ball without lubrication. It is found that the condition of generating carbon plasma (graphite sputtering or destruction of acetylene) has a significant effect on the structure and properties of CrAlSiC. CrAlSiC(I) consists of an amorphous phase with inclusions of silicon-carbide nanograins 10–30 nm in size. On the surface there are protrusions with a size of 2–4 µm. These features provide a high hardness and low friction coefficient. No crystalline formations are found in the amorphous matrix of CrAlSiC(II). On the surface there are bubble-like formations up to 15 microns in size. This coating is inferior to CrAlSiC(I) in terms of hardness and resistance to friction. Under friction the film is destroyed by chipping fragments. CrAlSiC(I) can be recommended for practical application.

A deposition technology of amorphous carbon coating (a-C), doped with copper (C-$$$Cu), has been developed. The C-Cu coating deposition was performed with the simultaneous operation of arc- and pulse-arc sources with copper and graphite cathodes, respectively. There was studied the antibacterial activity of the a-C and C-Cu against E. coli, S. aureus and P. aeruginosa. The copper-doped coating has bactericidal activity against P. aeruginosa. The number of bacterial colonies is five times lower in compare with a-C and Ti.

CrAlC and CrAlSiC films have been obtained and investigated. Simultaneous sputtering of graphite and Cr05Al05 or Cr035Al055Si0 08 targets was used for films deposition. The structure of the films is amorphous-nanocrystalline. The doping of CrAlC films with silicon is accompanied by an increase in their crystallinity due to the formation of silicon carbide particles. Structural changes make CrAlSiC films harder with a higher resistance to plastic deformation.

Single CrAlC, CrAlSiC and multilayer [CrAlC/a-C]n, [CrAlSiC/a-C]n coatings have been fabricated and investigated. Joint use of arc plasma source with Cr-Al(Si) cathode and pulsed arc plasma source with graphite cathode was applied to single coatings deposition. Diamond-like a-C layers alternate with CrAl(Si)C in multilayer coatings. The doping of CrAlC with silicon is accompanied by an increase in their crystallinity due to the formation of silicon carbide particles. Structural changes make CrAlSiC films harder with a low friction coefficient and a high resistance to plastic deformation. The multilayer coatings are crack resistant.

The structures, wear resistances, and corrosion behaviours of Cr-Al-C and multilayer [Cr-Al-C/a-C](n) coatings, fabricated by physical vapour deposition (PVD), plasma-assisted chemical vapour deposition (PACVD), or their combination, were studied. A Cr-Al target served as a source of chromium and aluminium, while a graphite target or acetylene served as sources of carbon. Depending on the type of carbon source, Cr-Al-C or Cr-Al-C(H) coatings were obtained. Multilayer [Cr-Al-C/a-C](20) and [Cr-Al-C(H)/a-C:H](20) coatings were fabricated by alternating pair layers of [Cr-Al-C (PVD)/a-C (PVD)] and [Cr-Al-C(H) (PVD-PACVD)/a-C:H (PACVD)], respectively. a-C and a-C:H are hydrogen-free and hydrogenated diamond-like carbons. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy were employed to investigate the coating structures. Along with the amorphous matrix, chromium carbide, and CrxAl1-xC nanograins, clusters of nanocrystalline graphite as spherical inclusions and plates, probably of several graphene layers, were observed in Cr-Al-C. This structure provided high hardness and corrosion resistance. Along with the amorphous matrix, Cr2AlC and chromium carbide nanoclusters and clusters of nanoscale CVD diamond with wide boundaries of sp(2) bonded carbon were observed in Cr-Al-C(H), whose hardness did not exceed 8.9 GPa. The multilayer structures significantly increased the wear resistances. The specific coefficient of wear rate (SCWR) of [Cr-Al-C/a-C](20) was five times lower than that of Cr-Al-C. Hybrid PVD-PACVD technology provided favourable conditions for the formation of wear-resistant coatings. The SCWR of [Cr-Al-C(H)/a-C:H](20) was 47 times lower than that of [Cr-Al-C/a-C](20). The high wear resistance of the multilayer coatings was associated with the structure, low friction coefficient, high crack resistance, and strengthened interface boundaries.

Hard multilayer coatings are technologically promising materials for reducing wear of tribological parts. Multilayer coatings with a systematic alternation of the pair [(TiCx/Ti/C)÷(a-C)] were deposited on stainless and tool steel by the PVD technique. Hardness (H), elasticity modulus (E) and critical cracking load (Pcr) were determined by the nanoindentation method. Nanofrictional wear test was conducted under multipass sliding of a diamond indenter (Ø 50 nm) under constant load. The specific coefficient of nanofrictional wear of [(TiCx/Ti/C)÷(a-C)]nwith different composition of titanium-containing layers was determined. The nanofrictional wear rate of [(TiCx/Ti/C)÷a-C]ndepends on the elastic and plastic characteristics of multilayer coating as a whole. Coatings having H3/E2> 0.12 and Pcr> 58 mN demonstrate low wear rate.

A focus point in this work was the research of the influence of deposition condition on properties of CrAlC films. CrAlC films were deposited by arc sputtering technique using arc sputtering of Cr-Al target and pulse arc sputtering of graphite target at different frequency. The multilayer [(CrAlC)+(a-C)]ncoatings were also obtained and investigated. Multilayer [(CrAlC)+(a-C)]nwere deposited with a systematic alternation of the pair [(CrAlC)+(a-C)], where a-C is the amorphous carbon layer. The structure, mechanical properties and fracture toughness of CrAlC films depend on pulse frequencies of the graphite sputtering. With increasing pulse frequency, the film structure changes from uniformly amorphous to amorphous with nanograins, the hardness of the films increases, the critical load of crack formation and film peeling tend to decrease. It is shown that a decrease in the thickness of the layers in [(CrAlC)+(a-C)]nleads to an increase in the crack resistance.

Amorphous carbon (a-C) and titanium-carbon nanocomposite TiCx/a-C coatings were deposited using the PVD technique. TiCx/a-C were deposited by simultaneous sputtering of graphite and titanium targets using arc pulse (at the frequency of 3 to 25Hz) and arc sputtering respectively. The composition, chemical structure and electrical properties of the surface have been studied by energy-dispersive X-ray spectroscopy, Raman spectroscopy and Kelvin probe force microscopy (KPFM). The increase in graphite sputtering arc pulse frequency is accompanied by the growth of carbon content in TiCx/a-C from 38 to 82at.% and by the change of phase composition. The incorporation of the Ti+ ions into the plasma flow of C+ increases the number of sp2 bonds in carbon matrix of TiCx/a-C, as compared to a-C deposited at the same frequency. The maps of contact potential difference (CPD) distribution over the surface of a-C and TiCx/a-C obtained by KPFM were used to calculate the root-mean-square (RMS) values of CPD. In a-C RMS of CPD decreases with scale up of arc pulse frequency. In TiCx/a-C RMS of CPD nonlinear depends on the carbon content and reaches maximum at CC=44at.%. It has been suggested, that at the contacts of different phases an interface thin layer is formed. The electronic properties of this layer differ from the electronic properties of the bulk phases of nanocomposite. The increase in volume fraction of interface component leads to the drop of RMS of CPD.

Recombinant human bone morphogenetic protein-2 with an additional s-tag domain (s-tag-BMP-2) synthesized in E. coli is characterized by higher solubility and activity than the protein without additional s-tag domain, which increases the yield during purification and simplifies protein introduction into the osteoplastic materials. The high osteoinductivity of the demineralized bone matrix with s-tag-BMP-2 was shown on the model of regeneration of cranial defects of a critical size in mice and on the model of implantation of porous titanium matrix into defects of femoral and tibial bones in rabbits.

В настоящей работе исследованы водородосодержащие алмазоподобные a-С:Н пленки, полученные деструкцией ацетилена в плазме несамостоятельного разряда, созданной с помощью плазменного катода. Электронно-микроскопические исследования выявили, что структура этих пленок аморфна, без кристаллических включений. Установлено, что физико-механические свойства пленок (твердость, внутренние напряжения, плотность) зависят от напряжения разряда. Наиболее твердые и плотные пленки получаются при напряжении разряда 200…300 В. Содержание аргона в пленках увеличивается с ростом напряжения разряда. Электросопротивление пленок резко падает при температуре отжига свыше 400 °C. Это является следствием графитизации. Контактный угол смачиваемости поверхности плёнок, осажденных на полимерные материалы, зависит от атмосферы (аргон-ацетиленовая или азот-ацетиленовая смесь) и напряжения разряда. Подобные пленки могут быть рекомендованы для повышения износостойкости рабочей поверхности изделий различного функционального назначения, в частности режущего инструмента.

Multilayer coatings [(TiCx/Ti/a-C)+ta-C]n with different composition of composite (TiCx/Ti/a-C) layers are studied. The dependences of abrasive wear resistance and H3/E2 ratio (H – hardness, E – elastic modulus) of multilayer coatings on the carbon content in the composite layer are determined. The phase composition of the (TiCx/Ti/a-C) layer, the ratio of volume fractions of the phases and the volume fraction of interface component, interlayer adhesion and adhesion to the substrate of the multilayer coating have a synergistic effect on the wear resistance of the testing coatings.

Open-porous titanium scaffolds have been widely investigated for orthopaedic and dental applications because of their ability to form composites via bone ingrowth into pores and promote implant fixation with mother bone. In this work, porous titanium scaffolds coated with a diamond-like carbon were produced, and their ability to form biocomposites was evaluated through in vivo experiments. Three types of the open-porous scaffolds made of spongy titanium granules (porosity 0.3, 0.4 and 0.5, Young’s modulus 4.4, 3.5 and 0.6 GPa) were implanted into a bone defect of sheep. Time dependences of the Young’s modulus of titanium scaffold–bone tissue biocomposites were determined through the measurement of Young’s modulus of the extracted scaffolds after 4, 8, 24 and 52 weeks of surgery. The Young’s modulus of biocomposite is dependent not only on the time of composite formation but also on the porosity of scaffold.