Ph.V. Kiryukhantsev-Korneev

Elemental analysis of coatings by high-frequency glow discharge optical emission spectroscopy

The physical basics of glow discharge optical emission spectroscopy are considered. The scheme of the system used for chemical analysis of coatings by glow discharge optical emission spectroscopy is described by the example of a Profiler 2 instrument (Horiba Jobin Yvon). Various types of coatings and methods for surface treatment are compared. On the basis of these studies, it is established that, under the basic measuring regimes without fine adjustment of sputtering parameters, the maximum analyzed depth of coatings is around 80 μm and the depth resolution is 10–20 nm. Almost any combinations of substrate and coating materials, including ceramics, glasses, and polymers, can be analyzed.

Characteristics and in vitro response of thin hydroxyapatite–titania films produced by plasma electrolytic oxidation of Ti alloys in electrolytes with particle additions

Enhanced incorporation of hydroxyapatite nanoparticles in porous titania coating formed by plasma electrolytic oxidation significantly increases surface osteogenic activity.

Multifunctional nanostructured coatings: Formation, structure, and the uniformity of measuring their mechanical and tribological properties

The state of the art of the studies in the field of the development and certification of novel multifunctional nanostructured coatings having a wide spectrum of applications is reviewed. The main tendencies in the optimization of the compositions and properties of the coatings are described, and the modern methods of diagnostics of the nanostructured coatings are considered.

Structure and properties of nanocomposite Mo—Si—B—(N) coatings

Coatings in the Mo—Si—B—(N) system are obtained using the magnetron sputtering method. Control of nitrogen and silicon content in the coatings is carried out using various gaseous Ar + N2 mixtures and variation of the number of Si segments in the area of MoSiB target erosion. The structure of coatings is studied using methods of scanning and transmission electron microscopy, X-ray analysis, infrared and optical emission spectroscopy, and Raman spectroscopy. Mechanical and tribological properties of the coatings are determined using methods of nanoindentation, scratch-testing, and tribological testing at temperatures of 25, 500, and 700°C. The oxidation resistance of coatings is studied. It is established that coatings with maximum Si and N content possess the best properties: hardness of 32 GPa, elastic recovery of 66%, low friction coefficient at high temperatures, and heat resistance up to 1200°C.

The influence of Si concentrations on the oxidation resistance of Mo-Si-B-(N) coatings

The influence of the silicon concentration on the oxidation resistance of Mo-Si-B-N coatings prepared by magnetron sputtering is investigated. The Si content in them was controlled by the composite-target composition, as well as by various areas of silicon segments placed into the target-erosion zone. The composition and structure of coatings after deposition and annealing in air at temperatures of 500–1300°C are investigated using transmission and scanning electron microscopy, energy-dispersive analysis, and glow-discharge optical emission spectroscopy. It is established that oxidation resistance increases as the Si concentration in coatings increases, which is caused by the formation of a silicon oxide-based dense layer; this layer prevents oxygen propagation into the coating depth upon heating. The maximal oxidation resistance at a level of 1300°C is attained in Mo-Si-B-N coatings containing 40 at % Si.

A comparative study of the structure and chemical properties of nanocomposite TiCaPCON-Ag coatings

To induce antibacterial activity in bioactive TiCaPCON coatings, materials have been doped with Ag in a quantity of 0.4–4.0 at %. Silver has been introduced into the coatings via two methods. Coatings with 0.4, 1.2, and 4.0 at % Ag content have been fabricated via simultaneous sputtering of a compositional TiC0.5-Ca3(PO4)2 target, which was obtained via self-propagating high temperature synthesis, and of a metallic Ag target. TiCaPCON-Ag (4.0 at %) coating was also fabricated via ion Ag implantation of preliminarily obtained TiCaPCON. The content and element distribution over the thickness of the coating were studied via glow discharge optical emission spectroscopy (GD-OES). The structure and morphology of the coatings have been probed via scanning electron microscopy. The results showed the formation of Ag particles in both the bulk and on the surface of the coatings, but their size and distribution over the coating thickness are found to depend on both the Ag concentration and method of sputtering of coatings. The effect of substrate temperature on Ag particle distribution in the coating is established. The study of kinetics of Ag dissolution via inductively coupled plasma mass-spectrometry and electrochemical methods has revealed that Ag dissolution rate is defined by the ratio of Ag nanoparticle size to the thickness of an oxide layer on the surface.

Ti-Cr-B-N coatings prepared by pulsed cathodic-arc evaporation of ceramic TiCrB target produced by SHS

The method of pulsed cathodic-arc evaporation of composite targets based on self-propagating high-temperature synthesis has been applied for the first time to prepare nanocomposite coatings in the Ti-Cr-B-N system. The influence of the deposition-process parameters on the coating structure and properties has been studied. Structural investigations have been carried out using X-ray diffraction analysis, transmission and scanning electron microscopy, glow-discharge optical-emission spectroscopy, and optical profilometry. The coating properties have been determined by nanoindentation and tribological tests. The results of the study show that the coatings mainly consist of highly dispersed fcc phase based on Ti(Cr)N in the form of crystallites 1–2 nm in size; in addition, amorphous BNx phase has been found to exist in the coatings. The coatings obtained under optimal conditions have the following parameters: hardness 20–24 GPa, friction coefficient ∼0.6, and reduced wear about 2 × 10−6 mm3 N−1 m−1.

Thermal Stability of Nanostructured Coatings

This paper is a review of the thermal stability of nanostructured nitride coatings synthesised by reactive magnetron sputtering technique. In the last three decade, nitride based coatings have been widely applied as hard wear-protective coatings in mechanical components. More recently, a larger interest has been addressed to evaluate the thermal stability of such coatings, as their mechanical and tribological properties are deteriorated at high working temperatures. This study describes the microstructural, mechanical and compositional stability of nano-crystalline Cr-N and nano-composited Ti-N based coatings (Ti-Al-Si-B-N and Ti-Cr-B-N) after air and vacuum annealing. For Cr-N coatings annealing in vacuum induces phase transformation from CrN to Cr2N, while after annealing in air only Cr2O3 phase is present. For Ti-N based coatings, a well-definite multilayered structure was shown after air annealing. Degradation of mechanical properties was observed for all the nitride coatings after thermal annealing in air.

Structure and properties of tribological coatings in Cu-B system

The effect of B additions on the structure and mechanical and tribological properties of Cu coatings produced by magnetron sputtering from mosaic targets has been investigated. It has been shown that the introduction of B results in structure refinement of the coatings. The hardness, elasticity modulus, elastic recovery, and plasticity index of Cu-B coatings have been determined. It has been established that the introduction of 7–15 at % of boron favors a decrease in the coefficient of friction and reduced wear. It has been shown that high tribological characteristics of coatings in the Cu-B system are connected with the formation of solid H3BO3 lubrication on the coating surface.

The effect of preliminary ion treatment on structure and chemical properties of polytetrafluoroethylene with a bioactive nanostructured coating

A comparative study of the effect of low-energy treatment with Ar ions, high-energy implantation with Ti ions, and subsequent deposition of bioactive nanostructured Ti-Ca-P-C-O-N coating on structure and properties of the polytetrafluoroethylene (PTFE) surface was carried out. The fcc phase based on titanium carbonitride with crystallite size of ∼20 nm was found to be the major structural component of the Ti-Ca-P-C-O-N coating deposited onto the PTFE support. The ionic treatment of the PTFE surface increases the edge angle of wetting from 100 to 128°. The deposition of the Ti-Ca-P-C-O-N coating onto smooth PTFE surface results in a significant decrease of the edge angle of wetting to 20°; whereas the deposition of the coating onto high-porosity PTFE surface after ion implantation results in complete spreading and absorption of a drop. The differences in electrochemical behavior of the PTFE samples coated with Ti-Ca-P-C-O-N were shown to be determined by different roughnesses and wettabilities.