The corrosion properties of aluminum bronze CuAl9Fe4Ni4Mn1 have been studied in a model environment simulating sea water under electrochemical corrosion conditions. Oxide-ceramic coatings were deposited on the surface and treatment with inhibitors was carried out to increase the corrosion resistance of the alloy. Oxide-ceramic coatings were applied by laser melting of powder mixtures on the surfaces of the samples using a fiber-optic short-pulse laser. Inhibitor treatment with solutions based on octanoic acid with nitrogen-containing compounds, such as benzotriazole, hydrazine hydrate and 2,4-dinitrophenylhydrazine, was carried out by impregnation. The phase composition, corrosion resistance in the environment simulating sea water, and surface of the samples were studied. The largest shift of the transpassivation potential to the positive region was observed for the TiO2-ZrO2 coatings. The mixture of octanoic acid and benzotriazole was the most efficient among the inhibitor mixtures studied.

The effect of cyclic electrochemical polarization on the corrosion properties of oxide -ceramic coatings consisting of transition metal oxides, boron carbide, and boron nitride was studied. The coatings were applied by laser melting of powder mixtures on the surface of low -carbon unalloyed steel using a fiber-optic laser. The resulting coatings feature enhanced tribological properties. The composition, surface condition, and resistance of samples to electrochemical corrosion were studied. Voltammetric curves were recorded in a neutral buffer solution. It was shown that the presence of boron nitride in the coating composition leads to depassivation of the steel surface. The conceptual possibility of enhancing the corrosion resistance of samples coated with B4C - BN - Bi2O3 - MnO2 by cyclic polarization was shown.

— Thin carbon films obtained on the surface of slide glass using the magnetron sputtering of a carbon target in an argon-gas medium are subjected to pulsed irradiation with argon ions with various pulse-repetition rates at a fixed ion energy of 30 keV and an irradiation dose of D = 10 17 cm –2 . It is shown that the electrical resistivity of carbon films depends nonmonotonically on the rate of dose selection during the implantation of argon ions. Raman spectroscopy and X-ray photoelectron spectroscopy are used to characterize carbon films, which makes it possible to explain the observed dependences of the electrical resistivity on the rate of dose selection during the implantation of argon ions.

Методами АСМ, РФЭС, РСА, механических и электрохимических испытаний изучено влияние имплантации инертных и химически активных ионов на формирование состава, структуры и модификацию физико-химических свойств тонких поверхностных слоев нержавеющей стали 03Х18Н11, титанового сплава ВТ6, армко-железа с напыленной пленкой углерода и армко-железа с напыленными пленками титан-алюминий. Показано, что имплантация ионов аргона, кислорода и азота приводит к повышению коррозионной стойкости стали 03Х18Н11 как в нейтральной среде, так и в среде, содержащей сильные активаторы коррозии - анионы хлорида. Установлено, что в условиях имплантации ионов N+ в титановый сплав ВТ6 формирование структурно-фазового состояния поверхностных слоев определяется химической активностью атомов азота к атомам титана. Облучение с высокими частотами следования импульсов, углеродных пленок на поверхности армко-железа, ионной имплантацией приводит к проявлению радиационно-термического эффекта, приводящего к коагуляции мелкодисперсных частиц в более крупные образования, и это сопровождается увеличением микротвердости пленок. Исследовано влияние перемешивания ионами аргона на формирование поверхностных слоев покрытия пленок алюминия и титана на подложке армко-железа. Определены параметры ионно-лучевого перемешивания, позволяющие сформировать интерметаллидные соединения (TiAl) в поверхностных слоях напыленной пленки титан-алюминий на подложке армко-железа. The influence of implantation of inert and chemically active ions on the formation of the composition, structure and modification of the physicochemical properties of thin surface layers of stainless steel 03X18N11, titanium alloy VT6, armco-iron with a carbon film sprayed and armco-iron with titanium-aluminum films sprayed has been studied by AFM, RFES, RSA mechanical and electrochemical tests. It is shown that the implantation of argon, oxygen and nitrogen ions leads to an increase in the corrosion resistance of steel 03X18H11 both in a neutral medium and in an environment containing strong corrosion activators - chloride anions. It is established that under the conditions of implantation of N+ ions into the titanium alloy VT6, the formation of the structural-phase state of the surface layers is determined by the chemical activity of nitrogen atoms to titanium atoms. Irradiation with high pulse repetition frequencies, carbon films on the surface of armco-iron, ion implantation leads to the manifestation of a radiation-thermal effect leading to coagulation of fine particles into larger formations, and this is accompanied by an increase in the microhardness of the films...

The surface layer obtained by ion-beam stirring of a thin carbon film deposited on titanium alloy VT6 is studied. The composition and the chemical condition of elements in the surface layer are determined. Formation of a disordered carbon structure in a thin surface layer (20 – 40 nm) and of titanium carbides in the transition layer is detected. A model of formation of structure in the specimens during irradiation is developed. It is shown that formation of a disordered carbon structure, of titanium carbides, and of dislocation substructures is responsible for elevation of the microhardness of the specimens after ion-beam stirring.

In this work, we consider the effect of irradiation in Ar+ -> O+ and O+ -> Ar+ sequences on changes in the chemical compound, type of chemical bond and the local atomic structure of ultrathin (similar to 20 nm) iron surface layers. Investigation of the chemical compound and the type of chemical bond of the ion-modified surface was carried out by the XPS (X-ray photoelectron spectroscopy) and Auger electron spectroscopy. The study of changes in the local atomic structure was carried out by an XAFS-like method - electron energy loss fine structure (EELFS) spectroscopy. The parameters of the local atomic environment of oxygen and iron - partial interatomic distances, dispersion parameters, and coordination numbers - were obtained by analyzing atomic pair correlation functions. Analysis of experimental data showed that the two-stage irradiation of iron significantly changes the chemical compound and local atomic structure of the initial surface. This leads to formation of an oxide layer of greater depth than in the case of irradiation with only oxygen ions.

A method for the surface chemical modification of aluminum oxyhydroxide (boehmite γ-AlO (OH)) by the nitrilotris(methylene phosphonic) acid (NTP) complexing ligand is proposed. The unmodified and NTP-modified boehmites are characterized using X-ray powder diffraction, XPS, and IR spectroscopy; the acid–base and complex-forming properties of surface-grafted NTP are studied. One of the three phosphonic groups of NTP is found to be involved in binding to the boehmite surface. The surface concentration and stepwise dissociation constants of grafted NTP are determined. A study of the nickel(II) sorption as a function of aqueous acidity shows that the modifying coating increases the sorption capacity of boehmite (causing рН 50 to shift by one unit toward lower values). In terms of surface complexation theory, nickel(II) sorption from aqueous solutions may be described by models involving ≡Al–ONi + and ≡Al–ONi(OH) complexes in the case of boehmite and ≡Al–LH i Ni i –3 ( i = 0, 1, 2, or 3) complexes in the case of NTP-modified boehmite (NTP-boehmite). NTP anchorage to the surface decreases the stability of nickel(II) complexes compared to their analogues in solutions. A mechanism of nickel(II) ion binding by NTP-boehmite is suggested. The prepared new organomineral support can be used to immobilize those metal ions that form stable complexes with phosphonic acids.

Abstract—The chemical composition and structure of thin surface layers of the Cu80Mn20 alloy before and after argon-ion irradiation in a pulse-periodic mode have been studied using X-ray electron spectroscopy and X-ray diffraction. It has been shown that the ion-beam action leads to the substantial redistribution of alloy components at depths exceeding the average path of projective range of argon ions. At the relative manganese concentration exceeding the content corresponding to the boundary of solid solution (Cu, γMn) homogeneity, the fcc structure, whose lattice parameters differ in depth, remains in the surface area of the irradiated Cu80Mn20 alloy. According to X-ray electron spectroscopy data, oxide forms of manganese are accumulated at the alloy surface; this leads to the improvement of passivation characteristics of the alloy. This may be related to the increase in the electrochemical activity of the alloy in the reaction of electoreduction of oxygen.

The composition and certain properties of the surface layer produced by oxygen-ion implantation into the Cu50Ni50 alloy are studied. Oxygen-ion implantation is shown to result predominantly in the oxidation of nickel, which is the more electronegative component of the alloy. Different forms of nickel oxide are concentrated mainly on the alloy surface. These oxide layers enhance the propensity of the alloy to passivation and a decrease in anodic currents in alkaline media. The effect of oxygen-ion implantation on the behavior of the alloy in neutral and acidic media is less obvious. Oxygen-ion implantation enhances the electrochemical activity of the alloy toward the oxygen-reduction reaction.

Short-pulse laser treatment was used to deposit boron carbide and nitride-based ceramic coatings on a non-alloy steel surface. The coatings thus obtained show promising properties in terms of high hardness, wear resistance, adhesion to the substrate, and low coefficient of friction. In parallel, the coatings obtained were characterized by reduced corrosion resistance in a model borate buffer solution and under conditions of recurrent water vapor condensation in a thermal humidity chamber. Preliminary treatment of samples with solutions of some inhibitors made it possible to reduce anodic currents substantially in potentiodynamic experiments. The addition of benzotriazole, mercaptobenzothiazole, and potassium dichromate proved to be effective. Electrochemical and atmospheric corrosion tests revealed that preliminary exposure of the samples to solutions of the inhibitors indicated above made it possible to reduce the corrosion rate significantly compared to the untreated samples. Potassium dichromate occurred to be most effective.

The effect of laser irradiation on the corrosion-electrochemical behavior of samples made of low-carbon unalloyed steel in borate buffer solution at pH 7.4 was studied. The modes of laser irradiation were determined (laser irradiation power 20 W; pulse frequency 100 kHz; line width of the trajectory of the laser beam 50 nm; scanning speed 350 (sample 2), 200 (sample 3), or 300 (sample 4) mm/s) ensuring the transition of steel to a passive state and a decrease in the overall rate of anodic dissolution of the metal. Laser irradiation of the samples was carried out in the air atmosphere. After laser treatment, some samples were studied in the same solution with addition of benzotriazole as a corrosion inhibitor. This inhibitor was chosen due to the fact that, like other azoles, it can be present in solution in the form of the initial molecules as well as in protonated form. It has been found that the nanoscale phases created by laser treatment decrease the surface oxidation rate under anodic polarization due to facilitation of transition to the passive state and thus favor an increase in the inhibitor efficiency. The results of XPS and microscopic studies show that laser surface treatment results in the formation of various types of adsorption centers. The assumption is substantiated that the adsorption centers after laser irradiation can be represented by various forms of iron oxides, including nonstoichometric, chemisorbed oxygen, as well as areas of nonoxidized (zero-valent) iron. Depending on the type of adsorption centers, benzotriazole molecules or possible protonation products can be adsorbed with formation of adsorption bonds of various nature.

The formation of nanoscale layers on the VT6 titanium alloy surface by ion-beam mixing of carbon with the N + ion implantation is investigated in this work. Ion-beam mixing in the transition layer of a film–carbon system on the VT6 alloy surface has been found to provide conditions for the formation of titanium carbides and nitrides. The thin surface layer (~10–20 nm) of the samples after both the deposition and ion-beam mixing of a carbon film mostly consists of carbon in a disordered state with sp 2 and sp 3 -hybridized C–C bonds. The formation of titanium carbides and nitrides in the transition layer, a disordered carbon structure in the thin surface layer, leads to a tenfold increase in the corrosion resistance of the samples.

Accumulation of nitrogen in nanosized surface layers of 03Kh17N12M2 stainless steel has been detected upon N + ion implantation up to 14 at % together with metal nitrides, mainly of chromium nitride CrN and interstitial solid solution. It has been demonstrated that N + ion implantation accompanied by preliminary irradiation by Ar + and O + ions decreases maximum nitrogen concentration by at least two times. It is assumed that this is stipulated by segregation to surface layers of iron atoms upon irradiation by Ar + ions as well as formation of chromium oxide Cr 2 O 3 and chromium hydroxide CrOOH upon irradiation by O + ions.

The accumulation of nitrogen to 14 at.% in the nanosized surface layers of samples of 03Х17Н12М2 stainless steel after implantation of N+ ions, the formation of metal nitrides, mainly CrN chromium nitride, and solid solution introduction has been established. It is shown that implantation of N+ ions using pretreatment by Ar+ and O+ ions leads to a decrease in the maximum nitrogen concentration by 2 or more times. It is assumed that this is due to segregation to the surface layers of iron atoms under irradiation by Ar+ ions and the formation of Cr2O3 chromium oxide and CrOOH chromium hydroxide under irradiation by O+ ions.