An overview of the use of electron spectroscopy for the study of the physico-chemical properties of solids is carried out. It is noted that the main source of information about the electronic states of atoms is the energy distribution of electrons excited by ions, X-ray quanta, and laser beams. The paper briefly discusses the problems that exist in registering the spectra of secondary electrons obtained by exciting the surface of samples with electrons of medium (1–20 keV) energies, and ways to solve these problems in order to increase the information content and accuracy of research results. A method for recording secondary electron spectra in an integral form using an Auger spectrometer is proposed, which allows to increase the energy resolution of the method. The possibilities of the method are demonstrated by the example of experimental studies of zirconium carbide and steel X17AG18.

The electronic spectra of high-nitrogen stainless Cr-Mn-N steel were studied depending on the type of its treatment: hardening, intensive surface shock treatment in the form of ultrasonic frequency hardening (UFH), and strain-heat treatment including successively performed UFH and electron beam heat treatment (EBT). Depth distribution profiles of element concentrations obtained by layer-by-layer Auger spectroscopy showed that during UFH, the steel surface is enriched with oxygen, which is likely to be located at sub-grain boundaries and linear defects of crystal lattice, since according to the results of the TEM study, there are no reflexes with large interplanar distances from oxides. The UFH + EBT processing allowed to form a sub-grain non-oriented structure with a fragment size not exceeding 30 nm, where CrN nitrides are evenly distributed in the austenite. Studies of electronic spectra have shown that the electronic levels in the atoms of high-nitrogen steel form configurations in which the interatomic Auger transitions are possible, because of which the Auger-peaks of chromium and manganese are shifted to the region of low energies at 5-14 eV. The increase in the number of linear defects and intergranular boundaries after UFH was found to affect the intensity and energy shifts of energy loss spectra on plasmons and spectra of secondary ion-electron emission.

The near-equiatomic TiNi shape memory alloy passivated through electropolishing and ion implantation with titanium has been studied toward corrosion performance in simulated body fluids (0.9 wt% NaCl, artificial blood plasma). Corrosion rate, nickel oxidation, repassivation and charge transfer has been examined by conventional methods of potentiodynamic polarization, electrochemical impedance spectroscopy and cyclic voltammetry. Experimental validation of the electrochemical results was performed using electron-microscopic (SEM/TEM) techniques and Auger electron spectroscopy. It was revealed that the thickness of the passive layer (TiO + TiO2) could be increased by similar to 5 times after ion implantation. Regardless of the corrosion environment, the TiNi alloys exhibiting different surface finishes still suffer from pitting corrosion associated with leaching of nickel ions via oxidation reaction. The Ti-implanted alloy shows satisfactory corrosion resistance in comparison with the reference electropolished TiNi alloy. After ion implantation, the dissolution of the surface layer during anodic polarization was restricted due to the formation of the Ni-depleted amorphous sublayer. Auger Ti-and Ni-LMM peaks are found to be shifted to lower energies due to the contribution of Ni-O and Ti-O bonding. It has been shown that not the thickness, but rather the structure and phase composition of the oxide layer are main factors responsible for corrosion performance.

The structure and mechanical properties of austenitic high-nitrogen steel (16.5 Cr, 18.8 Mn, 0.07 C, 0.53 N, 0.52 wt

The article presents the results of a study of vacuum-arc coatings obtained by the sputtering of Ti–B–Si–Ni cathodes fabricated using self-propagating high-temperature synthesis with simultaneous pressing. The techniques for manufacturing cathodes of the indicated composition are characterized; the modernized HNV 6.6-I1 installation, the conditions and modes of coating deposition in an argon atmosphere and in a nitrogen + argon gas mixture in the ratio of 90/10 are described. To study the physical and mechanical properties of the resulting coatings, the hardness is measured at different loads on the indenter; the strength of adhesion to the base is assessed by the Rockwell method; the elemental composition of the cathodes and the (Ti–B–Si–Ni)N coating is determined using Auger spectroscopy, and the phase composition of the (Ti–B–Si–Ni)N coating is determined using X-ray phase analysis; a study of the properties of the coating (Ti–B–Si–Ni) is carried out by scratch testing. As a result of a comprehensive analysis of the results obtained, it is concluded that the high hardness of the (Ti–B–Si–Ni)N coating (more than 40 GPa) is due to its composition, which includes both nitrides and high-hardness titanium borides. The heterophase nature of the structure of this coating can serve as a contribution to the stressed state of the material. The coating has a graded-layer structure. The material contains a Ti–B–Si–Ni layer bound to the substrate and the main functional layer (Ti–B–Si–Ni)N. The coating has both a high hardness and sufficient strength of adhesion to the base (adhesion) determined by scratch testing. The combination of these properties makes the material promising for its practical application in the production of tools.

The study investigates an electron beamcladded coating of nitrogen-alloyed austenitic steel (24.4Cr,16.4Mn, 0.18Ni, 1.1Si, 0.57С, 0.7N, rest Fe (wt %)). Cladding wasperformed by a continuous low-energy (27 keV) and low-current(0.02–0.04 A) focused electron beam on an electron beam system ata residual pressure of 0.1 Pa. The microstructure, phasecomposition, and chemical composition of the coating were examinedby OM/AES/XRD/SEM/EDS methods. The coating has no pores and ischaracterized by high work hardening and wear resistance. Theformation of М7(С, N)3 carbonitrides in thesteel plays a crucial role in the control of the structure andwear resistance of the applied coating, because carbonitrides areable to distinguish between the lattice curvature zones and thestable translationally invariant lattice. Frictional loads arisingduring wear trigger a γ → α′ transformation. With increasingfrictional load, the coefficient of friction decreases.

The change in the spectra of elastically and discretely scattered electrons inTi–6Al–4V alloy subjected to radial shear rolling at T = 1000°C was studied in comparison with the initial state.Interatomic bonds in the equilibrium α phase of the alloy are formed by Al spelectrons, and their contribution is small. Quenching after radial shear rollingat T = 1000°C causes the formation of anonequilibrium αʹ phase in the α phase. The resulting αʹ phase contains vanadiumatoms whose d electrons are part of the interatomic bond. As a result, the αphase is strengthened and the low-temperature toughness of the alloy isenhanced. At the same time, sp electrons are strongly scattered by vanadium ionsand therefore their contribution to the interatomic bond is weakened. Thisgenerates localized plastic flows in the lattice curvature zones, which developin the field of Coulomb repulsion of electrons and govern a high relaxationability of the alloy at low temperatures. Very high strengthening is found to befundamentally related to a very high relaxation factor. The results areexplained by the effect of structural transformation.

The paper studies the effect of the temperatureof helical rolling, which creates nanoscale mesoscopic structural statesin lattice curvature zones, on the low-temperature impact toughness ofTi–6Al–4V alloy. The polymorphic transformation temperatureTс = 950°C is shown to play the decisiverole in this effect. The impact toughness is very high at helicalrolling temperatures above Tс, while in thelow-temperature range up to T = –70°C it decreasesmonotonically. This is a very important aspect of the technology.Starting from the helical rolling temperature T =950°C, the toughness sharply decreases at T = –70°C. AtT = 900°C, it decreases sharply already atT = –20°C. At T = 850°C, the level ofthe entire toughness curve of the alloy is low. The high level of impacttoughness at T > Tс isfound to be due to a two-stage transformation of the bcc β phase into amixture of (α + β) phases. The first stage involves nonequilibriummicroscopic decomposition into the α and β phases. At the second stage,the nonequilibrium β phase decomposes into (α + β) subbands inaccordance with the interstitial structural states associated withlattice curvature. In helical rolling at T <Tс, the formation of martensite phases inthe close-packed lattice of the α phase of titanium reduces its impacttoughness. The fatigue life of Ti–6Al–4V alloy helically rolled atT = 1000°C remains unchanged.

The paper analyzes the nature of constantlow-temperature impact toughness in low-carbon low-alloy 10Mn2VNbAlsteel after helical rolling at 850°C. The analysis shows that whenrolled, the steel changes the electronic spectrum via shifting itslow-energy states in the reciprocal space of lattice curvature to higherlevels which are vacant in the initial material. Such interstitialstates provide the growth of interstitial bainite islands capable foradaptive rotations under shock loads, and this makes the rolled steelconstant in low-temperature impact toughness up toT = –70°C.

Abstract The coating produced by electron beam overlay welding of a nitrogen alloyed austenitic steel (24.40Cr, 16.40Mn, 0.18Ni, 1.1Si, 0.57C, 0.70N, and bal Fe (in wt.%)) is investigated. Electron beam overlay welding is performed by a continuous low-energy (27 keV), low-current (0.02–0.04 A) focused electron beam using electron beam setup (ISPMS SB RAS, Russia) with a residual pressure of 0.1 Pa. This paper examines microstructure, phase composition, chemical composition of the coating by OM/AES/XRD/SEM/EDS methods. The obtained coating is pore-free and exhibits high work hardening characteristics. Friction loads induce the γ;→α′ transformation in the wear process. With increasing friction loads, the friction coefficient decreases.

The effect of surface mechanical and heat treatment, which includes successive friction and electron-beam treatments, on the structure, mechanical properties, and the elastically deformed state of a 16.5 Cr–18.8 Mn–0.53 N–0.07 C steel has been studied in this work. The mechanical and heat treatment has been shown to refine the grain structure in the surface layer to a grain size of 2 μm, form a {100} 〈001〉 texture, and retain a deformation-hardened sublayer. A surface layer to 200 nm thick is enriched with oxygen, nitrogen, and carbon. X-ray diffraction has been used to study austenite lattice strains caused by residual stresses. The mechanical and heat treatment has been found to reduce the friction-induced elastic lattice contraction along the normal to the surface. The direction [100] is most sensitive to the effect of residual stresses and can serve as a marker when analyzing the nature of residual stresses in steels with structurally-changed plastically-undeformed surface layers.

In this study, Ti-Zr coatings were fabricated by ion-assisted arc-plasma deposition in vacuum. The phase composition, morphology and mechanical properties of the developed thin films were studied. The addition of Zr into Ti resulted in the formation of alpha'- (Ti,Zr) and alpha"- (Ti,Zr) solid solutions and mechanical properties change of the prepared alloys. It was revealed that the increase of Zr content in the coating resulted in the increase of nanohardness. The deposited coatings possess reduced modulus of elasticity 77-98 GPa, which is significantly improved compared with Ti substrate, which reveals a modulus of elasticity of 110 GPa. Furthermore, nanoindentation results demonstrate significant improvement of the elastic strain to failure and plastic deformation resistance of the Ti-Zr coatings with the increase of the content of Zr from 11 wt % to 22 wt%. Thus, it is likely that Ti-Zr coatings obtained by ion-assisted arc plasma deposition possess a high biomedical potential due to synergetic combination of biocompatibility and biomechanical properties. (C) 2017 Elsevier Ltd. All rights reserved.

The thickness, chemical and phase composition, adhesion characteristics of the near-surface layers of model samples from TiNi alloy after their plasma-immersion treatment using a magnetron system with silicon ions at different values of bias voltage on the sample were studied. It was found that as a result of processing on the samples surface was formed a two-layer coating based on silicon up to 2 mu m thickness. Near the surface there is a layer up to 20 nm thick, containing amorphous silicon and silicon oxide. In the deeper layers of silicon oxide is not found. It is shown that the coatings have a high adhesion to the substrate of NiTi alloy. The conclusion is made about the prospects of using the obtained silicon-based coatings to form a mesoporous structure in them for the purpose of placing therapeutic drugs in the pores in the manufacture of medical implants of NiTi alloy.

The features of the structure and the mechanical and tribotechnical properties of an austenitic nitrogen steel (Cr16.5, Mn18.8, C0.07, N0.53, Si0.52 wt %, and Fe for balance) after frictional treatment have been studied. It has been shown that, along with twinning, the nitrogen austenite upon frictional treatment undergoes a γ → stacking fault → ε transformation. The strengthening of the steel by the frictional treatment manifests in a delay of the onset of the plastic flow. In the structure of the surface layer with a thickness of 5 μm, a high concentration of stacking faults has been detected. The mechanical properties depend on the orientation of the acting stresses relative to the direction of the frictional treatment. Upon the sliding friction of a ball made of hard alloy (94%WC + 6%Co) on the strengthened surface, an anomalously low coefficient of friction of 0.13 is observed. The coefficient of friction in the presence of abrasive particles in the form of wear debris increases to 0.50; however, the wear rate is almost two times lower compared to the same characteristic for a nonstrengthened surface of the nitrogen steel tested under the same conditions.

The paper presents the research results in the synergies between the wear resistance of carbide cutting tools of P-group applicability and fractal dimension of the wear surface occurring on the rake face of the tool when processing the material, which causes intensive diffusion wear. It was found that the resistance of carbide cutting tools increases as the fractal dimension of their wear surface reduces.

A three-layer system of nanocrystalline hydroxyapatite (first layer; 1000nm thick), silver nanoparticles (second layer; 1.5μg Ag cm-2) and calcium phosphate (third layer, either 150 or 1000nm thick) on titanium was prepared by a combination of electrophoretic deposition of silver nanoparticles and the deposition of calcium phosphate by radio frequency magnetron sputtering. Scanning electron microscopy showed that the silver nanoparticles were evenly distributed over the surface. The adhesion of multilayered coating on the substrate was evaluated using the scratch test method. The resistance to cracking and delamination indicated that the multilayered coating has good resistance to contact damage. The release of silver ions from the hydroxyapatite/silver nanoparticle/calcium phosphate system into the phosphate-buffered saline (PBS) solution was measured by atomic absorption spectroscopy (AAS). Approximately one-third of the incorporated silver was released after 3days immersion into PBS, indicating a total release time of the order of weeks. There were no signs of cracks on the surface of the coating after immersion after various periods, indicating the excellent mechanical stability of the multilayered coating in the physiological environment. An antimicrobial effect against Escherichia coli was found for a 150nm thick outer layer of the calcium phosphate using a semi-quantitative turbidity test.

Ti-Al-N coatings were deposited on high-speed steel substrates by filtered vacuum arc deposition (FVAD) during evaporation of aluminum and titanium cathodes. Distribution of elements, phase composition, and mechanical properties of Ti-Al-N coatings were investigated using Auger electron spectroscopy (AES), X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindentation, respectively. Additionally, tribological tests and scratch tests of the coatings were performed. The stoichiometry of the coating changes from Ti0.6Al0.4N to Ti0.48Al0.52N with increasing aluminum arc current from 70 A to 90 A, respectively. XRD and TEM showed only face-centered cubic Ti-Al-N phase with preferred orientation of the crystallites in (220) direction with respect to the sample normal and without precipitates of AlN or intermetallics inside the coatings. Incorporation of Al into the TiN lattice caused shifting of the (220) reflex to a higher 2θ angle with increasing Al content. Low content and size of microdroplets were obtained using coaxial plasma filters, which provides good mechanical and tribological properties of the coatings. The highest value of microhardness (36 GPa) and the best wear-resistance were achieved for the coating with higher Al content, thus for Ti0.48Al0.52N. These coatings exhibit good adhesive properties up to 30 N load in the scratch tests.