Research

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16 pages, 25936 KiB

Open AccessArticle

Influence of Electron Beam Treatment on Structure and Phase Composition of TiB₂–Ag Coating Deposited by Electrical Explosion Spraying

by Artem D. Filyakov, Vasilii V. Pochetukha, Denis A. Romanov and Ekaterina S. Vashchuk

Coatings 2023, 13(11), 1867; https://doi.org/10.3390/coatings13111867 - 31 Oct 2023

Cited by 1 | Viewed by 899

Abstract

Due to many factors, the electrical explosion spraying process is not stable, which directly causes unstable coating quality and structure. Electron beam treatment may be used to improve the surface and modified structure of coatings sprayed by electrical explosions. In this study, a [...] Read more.

Due to many factors, the electrical explosion spraying process is not stable, which directly causes unstable coating quality and structure. Electron beam treatment may be used to improve the surface and modified structure of coatings sprayed by electrical explosions. In this study, a new TiB₂–Ag metal matrix composite coating was deposited by electrical explosion spraying and modified by electron beam treatment. The prepared coatings were characterized by surface macro- and microanalysis, XDR, cross-section SEM, and TEM. The composition of the spray-coating phase differs from sample to sample. The electron beam treatment normalized the phase composition. Ag TiB₂ B₂O became the main phase in the modified coating. Increasing the pulse energy density and duration leads to a reduction in the low-melting Ag phase and the formation of copper contact phases due to heating and melting of the copper substrate by excess electron beam energy. The coating structure consists of a silver matrix and TiB₂ inclusions. The electron beam treatment did not affect the structure; however, the microstructure of the coating transformed into a cellular crystallization structure. The silver matrix nanostructure was transformed into a nanocrystalline structure with an average crystal size ranging from tens to hundreds of nanometers. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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10 pages, 2516 KiB

Open AccessArticle

Controlling Bowing and Narrowing in SiO₂ Contact-Hole Etch Profiles Using Heptafluoropropyl Methyl Ether as an Etchant with Low Global Warming Potential

by Sanghyun You, Hyun Seok Yang, Dongjun Jeon, Heeyeop Chae and Chang-Koo Kim

Coatings 2023, 13(8), 1452; https://doi.org/10.3390/coatings13081452 - 17 Aug 2023

Viewed by 988

Abstract

Heptafluoropropyl methyl ether (HFE-347mcc3), as a lower-GWP (global warming potential) alternative to PFCs (perfluorocarbons), was used to etch SiO₂ contact holes. The etch profiles of the SiO₂ contact holes in HFE-347mcc3/O₂/Ar plasmas showed more bowing at lower flow rate [...] Read more.

Heptafluoropropyl methyl ether (HFE-347mcc3), as a lower-GWP (global warming potential) alternative to PFCs (perfluorocarbons), was used to etch SiO₂ contact holes. The etch profiles of the SiO₂ contact holes in HFE-347mcc3/O₂/Ar plasmas showed more bowing at lower flow rate ratios of HFE-347mcc3 to Ar, whereas more narrowing occurred at higher ratios. The measurements of the angular dependences of the deposition rates of fluorocarbon films on the surface of SiO₂ and the etch rates of SiO₂ showed that the shape evolution of contact-hole etch profiles at different HFE-347mcc3/Ar ratios was attributed to an increase in etch resistance and a decrease in etch ability of the sidewalls of the contact hole with the increasing HFE-347mcc3/Ar ratio. This resulted in determining the optimum ratio of HFE-347mcc3 to Ar to achieve the maximum anisotropy of the contact hole etched in HFE-347mcc3/O₂/Ar plasmas. By carefully selecting the specific flow rates of HFE-347mcc3/O₂/Ar (9/2/19 sccm), a highly anisotropic and bowing-free SiO₂ contact hole, with a 100 nm diameter and an aspect ratio of 24, was successfully achieved. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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18 pages, 1750 KiB

Open AccessArticle

Melting Thresholds of Materials Irradiated with a Wide Class of Pulsed Electron Beams

by Alexey Markov

Coatings 2023, 13(8), 1425; https://doi.org/10.3390/coatings13081425 - 14 Aug 2023

Cited by 2 | Viewed by 924

Abstract

Based on the proposed criterion of the type of heating, a classification of the sources of pulsed electron beams was carried out, both to obtain a better understanding of the nature of the thermal processes occurring under irradiation and to predict their suitability [...] Read more.

Based on the proposed criterion of the type of heating, a classification of the sources of pulsed electron beams was carried out, both to obtain a better understanding of the nature of the thermal processes occurring under irradiation and to predict their suitability for certain applications. The melting thresholds of materials were calculated over a wide ranges of accelerating voltages and pulse durations. On the basis of calculations, a refractoriness series was proposed for metals for surface–volume pulsed heating. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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13 pages, 2506 KiB

Open AccessArticle

Structure and Properties of Cermet Coatings Produced by Vacuum-Arc Evaporation of a High-Entropy Alloy

by Yurii F. Ivanov, Yuriy Kh. Akhmadeev, Olga V. Krysina, Nikolai N. Koval, Vladimir V. Shugurov, Elizaveta A. Petrikova, Nikita A. Prokopenko and Oleg S. Tolkachev

Coatings 2023, 13(8), 1381; https://doi.org/10.3390/coatings13081381 - 07 Aug 2023

Viewed by 917

Abstract

Multilayer cermet coatings based on a TiNbZrTaHf high-entropy alloy were produced on solid substrates by plasma-assisted vacuum-arc deposition. The assisting multicomponent metal-gas plasma was generated by evaporating TiNbZrTaHf cathodes in a gas mixture of nitrogen and argon. It was found that the coatings [...] Read more.

Multilayer cermet coatings based on a TiNbZrTaHf high-entropy alloy were produced on solid substrates by plasma-assisted vacuum-arc deposition. The assisting multicomponent metal-gas plasma was generated by evaporating TiNbZrTaHf cathodes in a gas mixture of nitrogen and argon. It was found that the coatings were nanocrystalline in structure (with nanocrystal sizes ranging from 2.5 to 4 nm). The metallic layer had a body-centered cubic lattice (a = 0.33396 nm), and the ceramic layer had a face-centered cubic lattice (a = 0.44465 nm). Transition layers formed between the substrate and the metallic layer and between the metallic and the ceramic layers were revealed. The hardness of the coatings was 36.7 GPa and their Young’s modulus was 323 GPa. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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12 pages, 5214 KiB

Open AccessArticle

Study on the Duration of Laser-Induced Thin Film Plasma Flash

by Guixia Wang, Junhong Su and Qingsong Wang

Coatings 2023, 13(8), 1323; https://doi.org/10.3390/coatings13081323 - 27 Jul 2023

Viewed by 672

Abstract

The accuracy of judging whether the film is damaged directly affects the accuracy of the measurement of the film laser damage threshold. When judging the film damage by the traditional plasma flash method, there is a problem of misjudgment caused by the failure [...] Read more.

The accuracy of judging whether the film is damaged directly affects the accuracy of the measurement of the film laser damage threshold. When judging the film damage by the traditional plasma flash method, there is a problem of misjudgment caused by the failure to distinguish the film and air plasma flash. In order to eliminate misjudgment, the two flashes are accurately distinguished by the difference in the duration of the air and film plasma flash. This paper aims to obtain the theoretical and experimental values of the duration of the film plasma flash (

t_{f}

) and analyze the factors affecting it. Firstly, taking single-layer hafnium oxide and aluminum oxide thin films as examples, when the wavelength of the incident laser is 1064 nm, the diameter of the laser focusing spot is 0.08 cm, the energy of the incident laser is 100 mJ, and the pulse width of incident laser is 10 ns, the

t_{f}

of hafnium oxide, and aluminum oxide thin films are 542.7 and 299.6 ns, respectively. Secondly, the experimental study of

t_{f}

was carried out. Through six experiments, the following results were obtained: (1) With the increase in incident laser energy, the

t_{f}

of both films increases; (2) The

t_{f}

of the hafnium oxide film is longer than that of the aluminum oxide film. (3) The experimental parameters are put into the calculation model, and the theoretical results are in good agreement with the experimental

t_{f}

values. Finally, it is found that

t_{f}

increases with the increase in incident laser energy and incident laser pulse width, and decreases with the increase in focusing spot diameter. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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12 pages, 2764 KiB

Open AccessArticle

Structure and Properties of CrN/TiN Multi-Layer Coatings Obtained by Vacuum-Arc Plasma-Assisted Deposition Method

by Andrey A. Leonov, Yuliya A. Denisova, Vladimir V. Denisov, Maxim S. Syrtanov, Alexander N. Shmakov, Viktor M. Savostikov and Anton D. Teresov

Coatings 2023, 13(2), 351; https://doi.org/10.3390/coatings13020351 - 03 Feb 2023

Cited by 12 | Viewed by 2074

Abstract

The paper presents the study results of CrN/TiN multi-layer coatings, as well as single-layer TiN and CrN coatings on Cr12MoV cold work die steel deposited by the vacuum-arc plasma-assisted method. Three CrN/TiN coatings of 8-, 16-, and 32-layers were deposited, in which the [...] Read more.

The paper presents the study results of CrN/TiN multi-layer coatings, as well as single-layer TiN and CrN coatings on Cr12MoV cold work die steel deposited by the vacuum-arc plasma-assisted method. Three CrN/TiN coatings of 8-, 16-, and 32-layers were deposited, in which the thickness of each layer was 500 nm, 250 nm and 125 nm, respectively. All of the coatings reveal a face-centered cubic structure with highly oriented (111) growth. The hardness of the CrN/TiN multi-layer coatings was about 27 GPa. Changing the architecture of CrN/TiN multi-layer coatings by reducing the thickness of the CrN and TiN layers from 500 nm to 125 nm promotes a smooth decrease in both the wear parameter and the coefficient of friction. By using an X-ray phase analysis with synchrotron radiation, it was found that 32-layer CrN/TiN coating retained thermal stability during heating in air to a temperature of 1120–1125 °C, and in a vacuum at least to a temperature of 1200 °C. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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9 pages, 2130 KiB

Open AccessArticle

Electron Beam Sintering of Composite Al₂O₃-ZrO₂ Ceramics in the Forevacuum Pressure Range

by Aleksandr Klimov, Ilya Bakeev, Efim Oks and Aleksey Zenin

Coatings 2022, 12(2), 278; https://doi.org/10.3390/coatings12020278 - 20 Feb 2022

Viewed by 1658

Abstract

We describe our investigations of electron beam sintering of multilayer ZrO₂-Al₂O₃ composite ceramics in the forevacuum pressure range (~30 Pa). To generate the electron beam, a plasma-cathode electron source operating in the forevacuum pressure range was used; this [...] Read more.

We describe our investigations of electron beam sintering of multilayer ZrO₂-Al₂O₃ composite ceramics in the forevacuum pressure range (~30 Pa). To generate the electron beam, a plasma-cathode electron source operating in the forevacuum pressure range was used; this kind of source provides the capability of direct processing of non-conducting materials. We studied the effect of electron beam sintering on the temperature drop with sample depth for different layer thicknesses and determined the optimal layer thickness to ensure minimal temperature drop. We show that in order to minimize the temperature difference and improve the sintering, it is necessary to take into account the thermophysical parameters of the sintered materials. Forming a layered structure taking into account the coefficient of thermal conductivity of the layer materials allows a reduction in the temperature gradient by 150 °C for samples of 3 mm thickness. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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Review

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39 pages, 9904 KiB

Open AccessReview

Electron-Beam Synthesis of Dielectric Coatings Using Forevacuum Plasma Electron Sources (Review)

by Yury G. Yushkov, Efim M. Oks, Andrey V. Tyunkov and Denis B. Zolotukhin

Coatings 2022, 12(1), 82; https://doi.org/10.3390/coatings12010082 - 12 Jan 2022

Cited by 11 | Viewed by 3112

Abstract

This is a review of current developments in the field of ion-plasma and beam methods of synthesis of protective and functional dielectric coatings. We give rationales for attractiveness and prospects of creating such coatings by electron-beam heating and following evaporation of dielectric targets. [...] Read more.

This is a review of current developments in the field of ion-plasma and beam methods of synthesis of protective and functional dielectric coatings. We give rationales for attractiveness and prospects of creating such coatings by electron-beam heating and following evaporation of dielectric targets. Forevacuum plasma electron sources, operating at elevated pressure values from units to hundreds of pascals, make it possible to exert the direct action of an electron beam on low-conductive materials. Electron-beam evaporation of aluminum oxide, boron, and silicon carbide targets is used to exemplify the particular features of electron-beam synthesis of such coatings and their parameters and characteristics. Full article

(This article belongs to the Special Issue Electron-Ion-Plasma Technology Applied to Surface Engineering)

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