N V Volkov

Radiation damage of material surfaces under prolonged irradiation with He + and Ar + ions with broad energy spectra

The results of studying the redistribution of Be, Al, Ti, Fe, Cu, Zr, Mo, and W atoms incorporated in polycrystalline metal samples under irradiation with He+, (He+ + Ar+), and Ar+ ion beams with a broad energy spectrum and an average energy of 10 keV at irradiation doses of 1 × 1021 ion/cm2 are studied. It is discovered that irradiation at doses exceeding 1 × 1019 ion/cm2 results in local small-crystal formations being produced in a near-surface substrate layer. Their typical dimensions are less than 1–5 μm, and their the density is up to 1–100. They contain incorporated atoms and impurity atoms with a concentration of 0.1–10 at %. Subsequent irradiation at a dose of 1 × 1020 ions/cm2 or more leads to disappearance of these formations, mainly because of sputtering processes.

The multicomponent doping of surface layers of materials under the influence of ion beams with a broad energy spectrum

The paper discusses the various factors that influence the efficiency of ion mixing. It was found that in the base of penetration of atoms multilayer films in polycrystalline substrate is the process of energy transfer from ions and primary knocked-on atom (PKA) of films to subsequent displacement cascade. At the same time the penetration of implanted atoms to great depths determined by the density of defects, radiation-stimulated migration of interstitial atoms and their physico-chemical interaction with the atoms of the matrix, which can be described by the model of an isotropic mixing. It is shown that doping atoms of the multilayer films, possibly the formation of gradient layers, which are determined by radiation traces in the substrate implanted atoms and their migration under irradiation by the ion beam with a broad energy spectrum.

Studies of the state of oxide films on a metal surface by IR spectroscopy methods

Molecular compounds containing relatively high amounts of oxohydrocarbons (-C-OH-O) have been revealed in metal oxides using the IR spectroscopy method. Scanning IR microscopy was used to analyze the oxide film state, and the principal possibility for determining the presence of different chemical compounds in local oxide parts with a linear resolution in the range 10–50 μm was demonstrated.

Optimizing the Parameters of Zr Alloy Doping with Al, Fe, and Mo via the Irradiation of Respective Films on Zr Surfaces Using Ar Ions

The effect the sputtering of a film–substrate system has on the modification of near-surface layers of zirconium alloy E110 (Zr–1% Nb) in the ionic mixing regime upon irradiation by a beam of argon ions with a wide energy spectrum is considered. It is shown that to increase the atoms’ efficiency of penetration and achieve the optimum doping conditions via ionic mixing upon irradiation by a beam of ions with a broad energy spectrum, the ion energy in the beam must be increased while simultaneously lowering the reduced atomic beam mass by using a combined ion beam of different masses.

Effect of ion polishing on corrosion resistance of the cladding of fuel elements from E110 alloy in the steam water environment

The method of modification of the outer surface of the cladding of fuel elements from E110 Zr alloy by means of irradiation with a radial beam of Ar+ ions with a broad energy spectrum is proposed. It is shown that the use of ion beam treatment at the final stage of the cladding production can improve the surface quality owing to removal of a large part of surface defects after mechanical polishing. The kinetics of the growth of oxide films on ion-beam-treated (cleaning or polishing by Ar+ ions) tubular Zr alloy specimens in a steam environment (350, 375, and 400°C up to 3000 h) was investigated. Monoclinic zirconia layer formation is found to occur on the specimen surface oxidized at 350°C in water and steam environments. Oxidation of the fragments of the alloy fuel-element cladding in steam under pressure contributes to the formation of a thicker and more friable oxide film in comparison with the oxidation in water.

Phase changes of iron near surface layers under argon ion irradiation

Mossbauer spectroscopy data on Ar+ ion irradiation influence on iron state are analyzed. It was shown the formation of new iron phases under Ar+ ion interaction with surface of zirconium alloy samples with iron and without iron layers. The appearance of paramagnetic phase in the surface layers was detected. Transformations of intermetallic compounds in zirconium alloys was established. Much changes are found in near surface layers.

Finish ion beam treatment of the longrange cylindrical products outer surface in automatic mode

The results of using of ion-beam technologies methods for finish treatment of metal products are presented. The experiments were performed at the installation ILUR-03, which allows the operation of cleaning, polishing and surface layers doping of the material of unlimited length cylindrical samples by radial Ar+ ions beam with energy up to 5 keV. The tubes from zirconium alloy E110 up to 500 mm length were used as samples for investigation. It is shown that selected automatic treatment modes reduce the surface roughness over the entire length of the samples and increase uniformity of the surface layer without observable effect on the bulk properties of material. Treatment promotes the formation of oxide films with improved defensive properties.

The impact of the initial state on the kinetics of oxidation ion- modified fuel cladding alloy E110

The paper examines the impact of the initial state (the presence of impurities, surface preparation), and surface alloying on the kinetics of the oxidation of fuel cladding alloy E110. The studies concluded that the use of ionic polishing instead of traditional chemical polishing helps to reduce the rate of oxidation of zirconium alloys. Also studied the effect of alloying elements introduced in the surface layers of claddings by ion mixing on the kinetics of the oxidation of the alloy E110.

Influence of thin oxide layers on tribological properties of E110 alloy tubular specimens under dry friction conditions

Experiments to simulate wear process of fuel cladding in case its contact with spacing grid. System «sphere-plane» selected as friction pair. Tubular parts of fuel claddings from E110 alloy diameter of 9.15 mm and length of 50 mm (wall thickness 1 mm) were used for investigations. Some claddings were subjected to ion cleaning and polishing under the influence of Ar+ ion beam with average energy of 3 keV. Samples were oxidized in steam- water conditions (T=300° C, p=17 MPa, time up to 100 h) to create thin oxide layers with a thickness of 1 mkm on the tubes surface. It is found that wear of the metallic samples takes place in elastically plastic deformation conditions at initial stage (2-5 min). Presenceof thin oxide layer (of thickness up to 200 nm) on the samples surface contributes to reduce wear due to the uniform redistribution its fragments on the friction track, and wear also samples takes place in elastically plastic deformation conditions. Presence of oxide layer with thickness of 700 nm on the samples surface increases wear in conditions of abrasion friction.

Modifying a cylindrical surface irradiated with a radial beam of argon ions with energies of up to 5 keV

Aspects of the ion modification of the outer surfaces of tubular samples of E110 (Zr–1% Nb) alloy is studied. The samples are irradiated with a radial beam of argon ions (0.5–5.0 keV, (5–10) × 1018 ion/cm2) on the ILUR-03 setup. It is found that such ion bombardment smooths the relief formed by mechanical abrasive treatment. It is demonstrated that the effect of ion polishing is most pronounced for surface irregularities of a certain size.