Yu H Akhmadeev

Institute of High Current Electronics

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N. N. Koval

Institute of High Current Electronics

I. V. Lopatin

Institute of High Current Electronics

ЕА

Е. А. Петрикова

Institute of High Current Electronics

Yu. F. Ivanov

Institute of High Current Electronics

ОВ

О. В. Крысина

Institute of High Current Electronics

ВВ

В. В. Шугуров

Institute of High Current Electronics

N. A. Prokopenko

Institute of High Current Electronics

ОС

О. С. Толкачев

National Research Tomsk State University

P. M. Schanin

Institute of High Current Electronics

ВВ

В. В. Денисов

Institute of High Current Electronics

Cooperative Institutions

National Research Tomsk State University

Institute of High Current Electronics

Siberian Branch of the Russian Academy of Sciences

Russian Academy of Sciences

Tomsk Polytechnic University

Institute of Strength Physics and Materials Science

Plasma (Russia)

University of Rome Tor Vergata

National Centre for Nuclear Research

Kurchatov Institute

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EVOLUTION OF THE AISI 5135 STEEL STRUCTURE AND PROPERTIES UNDER ELION NITRIDING IN LOW-PRESSURE GAS DISCHARGE

High Temperature Material Processes An International Quarterly of High-Technology Plasma Processes (2022)

I. V. Lopatin Yu H Akhmadeev Е. А. Петрикова M E Rygina Yu. F. Ivanov

A method and experiments for nitride AISI 5135 steel with simultaneous heating of the samples by the electron component of plasma are described. A nitriding regime that makes it possible to form a hardened layer up to 240 μm thick is explained. It is shown that the microhardness of the surface layer increases with an increase in the nitriding temperature. It is further demonstrated that the microhardness correlates with the relative content of the nitride phase. The maximum microhardness was recorded in the subsurface layer at the depth of ≈ 10 μm regardless of the nitriding temperature. The wear resistance depends on the concentration of nitrogen atoms in the α-Fe crystal structure; the saturation of the α-Fe crystal structure with nitrogen contributes to an increase in material wear under dry friction.

Iron nitride

Crystal (programming language)

Saturation (graph theory)

10.1615/hightempmatproc.2022043197

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High-current-density gas ion ribbon beam formation

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2018)

A. I. Ryabchikov D. O. Sivin О. С. Корнева I. V. Lopatin P.S. Anan'in

Ion gun

Ion current

Ribbon

10.1016/j.nima.2018.07.088

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Citations (8)

Plasma generation in the arc discharge with a thermionic cathode in current stabilization conditions

Journal of Physics Conference Series (2019)

I. V. Lopatin Yu H Akhmadeev N. N. Koval S. S. Kovalsky

Abstract The paper investigates plasma generation in a PINK plasma generator with thermionic and hollow cathodes under stabilizeddischarge current. The possibility of not completely closing of the thermionic electrons current into an external circuit is shown under these conditions. The current of emitted from the thermionic cathode electrons mostly closes inside the device, thus increasing the thermal and current load on the electrodes under such conditions. At this, the current direction in the hollow cathode circuit may change, which has no effecton external circuits. It is further shown that the redistribution of currents in the electrode circuits depends on the discharge conditions (including thermionic cathode heating current and voltage, as well as operating pressure and type of working gas), which, in turn, have influence on the instantaneous potentials of the cathode electrodes. Studies of the main plasma characteristics in different phases of the thermionic cathode heating current and under different plasma generation conditions have shown that changing the current direction in the hollow cathode circuit has in significant influence on the instantaneous values of the main plasma parameters, however, plasma generation is not optimalunder these conditions.

Thermionic emission

Hot cathode

Cold cathode

Electric arc

10.1088/1742-6596/1393/1/012046

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ELECTRON BEAM TREATMENT AND HARD ANODIC OXIDATION OF ALSI7 ALLOYS TO IMPROVE THE ANODIC OXIDE PROPERTIES

M. Bestetti Andrea Lucchini Huspek B. Akdogan Yu H Akhmadeev Е. А. Петрикова

7 92 5-0 65 5-8-2 02 3-1 75-182 Al-Si alloys are among the most common aluminium-based cast products due to their high strength-toweight ratio, excellent processability and relatively low cost.Their surface mechanical properties and corro sion resistance are usually enhanced by forming a protective anodic oxide coating by means of hard anodic oxidation.However, the presence of silicon particles within the aluminium matrix decreases the quality and integrity of the anodic oxide.In the present work, R ITM -SP and SO LO electron beam facilities are used to modify the distribution of silicon in the surface region of the alloy.The hard anodic oxides produced after electron beam pre-treatment were characterized by S E M -E D S and in term of corrosion resistance properties.

Anodic oxidation

10.31554/978-5-7925-0655-8-2023-175-182

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Generation of low-temperature gas discharge plasma in large vacuum volumes for plasma chemical processes

Russian Journal of General Chemistry (2015)

N. N. Koval Yu. F. Ivanov I. V. Lopatin Yu H Akhmadeev В. В. Шугуров

Vacuum chamber

Electric arc

Plasma cleaning

10.1134/s1070363215050485

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Citations (38)

Low energy implantation of nitrogen ions by extended beam with a ballistic focusing in a stainless steel

Journal of Physics Conference Series (2019)

A. I. Ryabchikov Yu H Akhmadeev I. V. Lopatin О. В. Крысина D. O. Sivin

Abstract The results of experiments on low-energy nitrogen ions implantation in stainless steel AISI 321 are presented. The treatment was carried out with a pulsed beam of nitrogen ions obtained using a ballistic system of ion focusing. The source of ions was nitrogen plasma of a non-independent gas arc discharge with a heated cathode. It was shown that the specimen surface is subjected to ion etching, which leads to the formation of a well, whose profile depends on the ionic exposure parameters. In addition, when treating specimen in such a system, the surface hardness increases up to 4 times. The increase in hardness occurs due to the formation of a modified layer in the surface, with a thickness of up to 50 microns, containing iron and chromium nitrides.

10.1088/1742-6596/1393/1/012125

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Plasma sources based on a low-pressure arc discharge

Laser and Particle Beams (2003)

Yu H Akhmadeev S. V. Grigoriev N. N. Koval P. M. Schanin

This article presents two types of a hollow-cathode plasma source based on an arc discharge where the electrons emitted either by a hot filament or by a surface-discharge-based trigger system initiate a gas arc discharge. The sources produce gas plasmas of densities 10 10 –10 12 cm −3 in large volumes of up to 0.5 m 3 at a discharge current of 100–200 A and at a pressure of 10 −1 –10 −2 Pa. Consideration is given to some peculiarities of the operation of the plasma sources with various working gases (Ar, N 2, O 2 ). The erosion rate of the cold hollow cathode in the designed plasma sources is shown to be 10 times lower than that found in an ordinary one. The sources are employed for plasma-assisted surface modification of solids.

Electric arc

10.1017/s0263034603212131

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Citations (14)

Plasma source based on arc discharge with cold hollow cathode

Yu H Akhmadeev S. V. Grigoriev N. N. Koval I. V. Lopatin P. M. Schanin

Summary form only given, as follows. In a low-pressure arc discharge a dense low-temperature plasma is effectively generated. This plasma finds an application, both in scientific examinations, and in technological purposes. One of the essential disadvantages restricting technological application of an arc discharge with a cathode spot is the presence of a considerable part of a micro-droplet fraction in a plasma flow. In the report the construction, operating principle and main characteristics of an arc plasma source for producing a homogeneous gas-discharge plasma with microdroplet fraction in big vacuum volumes is given. The plasma source is based on an arc discharge with a cathode spot.

Electric arc

Plasma arc welding

Plasma torch

Vacuum arc

10.1109/plasma.2003.1228682

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Multi-element nitride coatings of quasi-equiatomic composition synthetized by the ion-plasma method

Izvestiya vysshikh uchebnykh zavedenii Fizika (2022)

Yu. F. Ivanov Yu H Akhmadeev N. N. Koval В. В. Шугуров E.A. Petrikova

Multi-element nitride coatings of quasi-equiatomic composition (NbMoCrTiAl)N and (NbZrCu-TiAl)N are synthesized by deposition on a substrate in vacuum from a multicomponent gas-metal plasma. This plasma was generated by simultaneous independent vacuum-arc evaporation of the cathodes of the selected elements in the regime with plasma assistance in a nitrogen atmosphere. It has been established that the synthesized coatings are single-phase materials with a face-centered cubic crystal lattice. For the coating composition (NbZrCuTiAl)N, the crystal lattice parameter was a = 0.44288 nm, and for (NbMoCrTiAl)N it was a = 0.40540 nm. The formed nitride coatings have a nanocrystalline multilayer structure. The microhardness of the coatings depends on the concentration and type of chemical elements, nitrogen pressure in gas-metal plasma. The microhardness reaches 43 GPa for the (NbMoCrTiAl)N coating and 46.5 GPa for the (NbZrCuTiAl)N coating.

Nanocrystalline material

Lattice constant

10.17223/00213411/65/11/59

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PLASMA GENERATION IN A LOW-PRESSURE HOLLOW-CATHODE NON-SELF-SUSTAINED GLOW DISCHARGE

High Temperature Material Processes An International Quarterly of High-Technology Plasma Processes (2013)

I. V. Lopatin Yu H Akhmadeev N. N. Koval P. M. Schanin

Research on a hollow-cathode non-self-sustained glow discharge demonstrates the feasibility of discharge operation at pressures from 0.1 Pa. Depending on experimental conditions, the discharge operating voltage can reach ~50 V, which is much lower than that of a self-sustained glow discharge in the same electrode system. The discharge current can range up to 30 A. The working gas is Ar, N2, and N-based gas mixtures. Probe measurements of the discharge plasma show that the electron temperature varies between 1.5 and 7 eV, depending on the pressure of gas and its kind, and the plasma density can reach 1011 cm−3 at 15-A currents. Nitriding in the discharge plasma at 600°C for 2 h made it possible to increase the hardness of Ti (VT1-0) 3.5 times and that of 12Cr18Ni10Ti three times, with a modified layer depth of 35 µm.

Glow discharge

Gas pressure

Discharge pressure

10.1615/hightempmatproc.2015013717

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Citations (2)