Amorphous and High-Entropy Alloy Coatings

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Corrosion and Protection".

Deadline for manuscript submissions: closed (30 November 2022) | Viewed by 36116

Special Issue Editors


E-Mail Website
Guest Editor
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
Interests: metallic glasses; coatings; powder metallurgy; additive manufacturing; corrosion; mechanical properties
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
National Key Laboratory for Remanufacturing, Beijing 100072, China
Interests: surface protection; additive remanufacturing of materials

E-Mail Website
Guest Editor
Metallurgy and Materials Science Research Institute, Michoacana University of San Nicolas of Hidalgo, Morelia 58030, Michoacan, Mexico
Interests: synthesis of Nanocrystalline and amorphous materials; structural characterization; surface treatment; microstructural characterization; thin films; mechanical properties
Special Issues, Collections and Topics in MDPI journals

E-Mail Website1 Website2
Guest Editor
Beijing Advanced Innovation Center of Materials Genome Engineering, State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, 30 XueyuanRoad, Beijing 100083, China
Interests: high-entropy materials and amorphous alloys; serration and noise in materials; meta-materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Amorphous and high-entropy alloy coatings present high hardness/strength and excellent wear as well as corrosion resistance, and thus have been widely utilized to enhance the surface performance of structural materials. These coatings can be obtained using different processes, such as HVOF, laser cladding, plasma spraying, cold spraying, and others. In recent years, a number of investigations into these coatings have been made in terms of their synthesis, microstructures, properties, mechanisms, and applications from the viewpoint of simulations and experiments. This Special Issue is mainly focused on the current status of the research and development of amorphous and high-entropy alloy coatings concerning these related themes. It is expected that the related works can provide insights into the intrinsic characteristics and further industrial applications of these coatings.

Prof. Dr. Jianqiang Wang
Dr. Xiaoming Wang
Prof. Dr. Ariosto Medina
Prof. Dr. Yong Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • amorphous coatings
  • amorphous/nanocomposite phase
  • hardness
  • adhesion
  • corrosion
  • wear resistance
  • thermal spray
  • application

Published Papers (14 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

13 pages, 8504 KiB  
Article
Preparation and Microstructure of Multi-Component High Entropy Alloy Powders Fabricated by Gas Atomization Method
by Zhiqiang Ren, Sheng Zhu, Xiaoming Wang, Yang Zhao, Guofeng Han, Kebing Zhou, Wenyu Wang and Gen Tian
Metals 2023, 13(2), 432; https://doi.org/10.3390/met13020432 - 20 Feb 2023
Cited by 4 | Viewed by 1748
Abstract
As an attractive high-entropy alloy, AlCrCoNiCu high-entropy alloy has excellent corrosion resistance, wear resistance, and anti-bacterial capabilities, and is considered to be a potential substitute material for marine and nuclear industry materials with great potential. One key to further optimizing the performance of [...] Read more.
As an attractive high-entropy alloy, AlCrCoNiCu high-entropy alloy has excellent corrosion resistance, wear resistance, and anti-bacterial capabilities, and is considered to be a potential substitute material for marine and nuclear industry materials with great potential. One key to further optimizing the performance of high entropy alloy was to prepare high entropy alloy powder materials with uniform composition, good flow-ability, and stable performance. In this work, the AlCrCoNiCu high entropy alloy powder was prepared by the gas atomization method. The results indicated that the powder was spherical in shape, homogeneous in composition, and composed of a face-center cubic (FCC) phase. After adding Fe and Mn elements, FCC and body-center cubic (BCC) phases appeared and the particle size of the powder was mainly located at 10–50 μm. Furthermore, the larger the particle size was, the more obvious the surface roughness was. With the decreasing powder size, its shape became relatively regular, and the surface roughness decreased. This work provided an experimental and theoretical reference for preparing high-performance single-phase and multi-phase high entropy alloy spherical powders. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

14 pages, 4971 KiB  
Article
Phase Prediction and Visualized Design Process of High Entropy Alloys via Machine Learned Methodology
by Jin Gao, Yifan Wang, Jianxin Hou, Junhua You, Keqiang Qiu, Suode Zhang and Jianqiang Wang
Metals 2023, 13(2), 283; https://doi.org/10.3390/met13020283 - 31 Jan 2023
Cited by 4 | Viewed by 1840
Abstract
High entropy alloys, which contain five or more elements in equal atomic concentrations, tend to exhibit remarkable mechanical and physical properties that are typically dependent on their phase constitution. In this work, a based leaner and four ensemble machine learning models are carried [...] Read more.
High entropy alloys, which contain five or more elements in equal atomic concentrations, tend to exhibit remarkable mechanical and physical properties that are typically dependent on their phase constitution. In this work, a based leaner and four ensemble machine learning models are carried out to predict the phase of high entropy alloys in a database consisting of 511 labeled data. Before the models are trained, features based on the empirical design principles are selected through XGBoost, taking into account the relative importance of each feature. The ensemble learning methods of Voting and Stacking stand out among these algorithms, with a predictive accuracy of over 92%. In addition, the alloy designing process is visualized by a decision tree, introducing a new criterion for identifying phases of FCC, BCC, and FCC + BCC in high entropy alloys. These findings provide valuable information for selecting important features and suitable machine learning models in the design of high entropy alloys. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

11 pages, 3921 KiB  
Article
Electrochemical Corrosion Behavior of CrFeCoNi and CrMnFeCoNi Coatings in Salt Solution
by Caimei Wang, Yang Yu, Peng He, Jianjun Zhang, Xiaoyu Ma, Hua Zhang, Huizhao Li and Minghao Shao
Metals 2022, 12(10), 1752; https://doi.org/10.3390/met12101752 - 18 Oct 2022
Viewed by 1201
Abstract
CrFeCoNi and CrMnFeCoNi coatings were prepared by laser remelting method. The grain boundary characteristics distribution of both coatings was investigated by electron backscattered diffraction technique. The results showed that the CrFeCoNi coating exhibited higher fraction of low angle grain boundaries and Σ3 boundaries [...] Read more.
CrFeCoNi and CrMnFeCoNi coatings were prepared by laser remelting method. The grain boundary characteristics distribution of both coatings was investigated by electron backscattered diffraction technique. The results showed that the CrFeCoNi coating exhibited higher fraction of low angle grain boundaries and Σ3 boundaries compared to the CrMnFeCoNi coating. The corrosion properties of the CrFeCoNi and CrMnFeCoNi coatings in 3.5 wt% NaCl solution were identified by electrochemical method and localized electrochemical impedance spectroscopy technique. The results indicated that the CrFeCoNi coating had a higher corrosion resistance than the CrMnFeCoNi coating. The better corrosion resistance of the CrFeCoNi coating could be attributed to the high fraction of Σ3 boundaries and low fraction of the high angle boundaries. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

18 pages, 4832 KiB  
Article
Microstructures, Mechanical Behavior, and Radiation Damage of (TiVCr)x-(TaW)1-x Binary System High-Entropy Alloy Films
by Rongbin Li, Tian Huang, Jing Zhang, Chunxia Jiang, Yong Zhang and Peter K. Liaw
Metals 2022, 12(5), 772; https://doi.org/10.3390/met12050772 - 29 Apr 2022
Cited by 4 | Viewed by 1572
Abstract
An experimental method for preparing high-entropy thin films with gradient changes of alloying elements by magnetron sputtering co-deposition is proposed in this work to evaluate the effect of alloying element composition changes on the properties of non-equal molar ratio high-entropy alloys. The (TiVCr)x-(TaW)1-x [...] Read more.
An experimental method for preparing high-entropy thin films with gradient changes of alloying elements by magnetron sputtering co-deposition is proposed in this work to evaluate the effect of alloying element composition changes on the properties of non-equal molar ratio high-entropy alloys. The (TiVCr)x-(TaW)1-x binary system thin films were deposited by a magnetron sputtering system with two intermediate alloy targets. The surface morphology, element composition, roughness, and phase structure of the coatings were studied with scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffractometer (XRD), atomic force microscope (AFM), and transmission electron microscope (TEM). The results show that at x = 0.51, the films had the best mechanical properties under the action of multiple strengthening mechanisms, and the hardness and modulus reached 27.61 GPa and 274.42 GPa, respectively. Due to higher hardness and special surface morphology, the films showed a lower average friction coefficient and had excellent wear resistance with wear rates of 0.34 and 5.01 × 10−9 mm3/(N·mm), respectively. On the other hand, it was found that forming a BCC polycrystalline structure and an amorphous-mixed structure can improve the radiation resistance of the material. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

13 pages, 9572 KiB  
Article
A Strategic Design Route to Find a Depleted Uranium High-Entropy Alloy with Great Strength
by Weiran Zhang, Yasong Li, Peter K. Liaw and Yong Zhang
Metals 2022, 12(4), 699; https://doi.org/10.3390/met12040699 - 18 Apr 2022
Cited by 5 | Viewed by 2204
Abstract
The empirical parameters of mixing enthalpy (ΔHmix), mixing entropy (ΔSmix), atomic radius difference (δ), valence electron concentration (VEC), etc., are used in this study to design a depleted uranium high-entropy alloy (HEA). X-ray diffraction (XRD), scanning electron [...] Read more.
The empirical parameters of mixing enthalpy (ΔHmix), mixing entropy (ΔSmix), atomic radius difference (δ), valence electron concentration (VEC), etc., are used in this study to design a depleted uranium high-entropy alloy (HEA). X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to assess the phase composition. Compression and hardness tests were conducted to select alloy constituents with outstanding mechanical properties. Based on the experimental results, the empirical criteria of HEAs are an effective means to develop depleted uranium high-entropy alloys (DUHEAs). Finally, we created UNb0.5Zr0.5Mo0.5 and UNb0.5Zr0.5Ti0.2Mo0.2 HEAs with outstanding all-round characteristics. Both alloys were composed of a single BCC structure. The hardness and strength of UNb0.5Zr0.5Mo0.5 and UNb0.5Zr0.5Ti0.2Mo0.2 were 305 HB and 1452 MPa, and 297 HB and 1157 MPa, respectively. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

11 pages, 11255 KiB  
Article
Microstructures and Properties of the Low-Density Al15Zr40Ti28Nb12M(Cr, Mo, Si)5 High-Entropy Alloys
by Yasong Li, Peter K. Liaw and Yong Zhang
Metals 2022, 12(3), 496; https://doi.org/10.3390/met12030496 - 15 Mar 2022
Cited by 20 | Viewed by 2792
Abstract
Low-density materials show promising prospects for industrial application in engineering, and have remained a research hotspot. The ingots of Al15Zr40Ti28Nb12Cr5, Al15Zr40Ti28Nb12Mo5 and Al15 [...] Read more.
Low-density materials show promising prospects for industrial application in engineering, and have remained a research hotspot. The ingots of Al15Zr40Ti28Nb12Cr5, Al15Zr40Ti28Nb12Mo5 and Al15Zr40Ti28Nb12Si5 high-entropy alloys were prepared using an arc melting method. With the addition of the Cr, Mo, and Si, the phase structures of these alloys changed to a dual phase. The Cr and Mo promote the formation of the B2 phase, while the Si promotes the formation of a large amount of the silicides. The compression yield strengths of these alloys are ~1.36 GPa, ~1.27 GPa, and ~1.35 GPa, respectively. The addition of Si and Cr significantly reduces the compression ductility, and the Al15Zr40Ti28Nb12SiMo5 high-entropy alloy exhibits excellent comprehensive mechanical properties. This work investigated the influence of Cr, Mo, and Si on the phase structures and properties of the low-density Al-Zr-Ti-Nb high-entropy alloys, providing theoretical and scientific support for the development of advanced low-density alloys. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

17 pages, 3180 KiB  
Article
Evolution of Face-Centered Cubic Ti Alloys Transformation by X-ray Diffraction Profile Analysis in Mechanical Alloying
by Edgar Pio, Ariosto Medina, Carola Martínez, Felipe Manuel Castro Cerda and Claudio Aguilar
Metals 2021, 11(11), 1841; https://doi.org/10.3390/met11111841 - 16 Nov 2021
Cited by 3 | Viewed by 2610
Abstract
Four titanium alloys (Ti-Ta, Ti-Ta-Sn, Ti-Ta-Mn, and Ti-Nb-Sn) were synthesized by mechanical alloying (MA) in a planetary mill in different times between 2 h and 100 h. The microstructure characterization was made by X-ray diffraction (XRD), in which the Rietveld method was applied [...] Read more.
Four titanium alloys (Ti-Ta, Ti-Ta-Sn, Ti-Ta-Mn, and Ti-Nb-Sn) were synthesized by mechanical alloying (MA) in a planetary mill in different times between 2 h and 100 h. The microstructure characterization was made by X-ray diffraction (XRD), in which the Rietveld method was applied to analyze the diffraction patterns. The study demonstrated that after short milling times between 2 h and 30 h, the fraction of hexagonal close-packed (hcp) phase decreases; at the same time, the formation of body-centered cubic (bcc) and face-centered cubic (fcc) Ti phases are promoted. Additionally, after 30 h of MA, the full transformation of hcp-Ti was observed, and the bcc-Ti to fcc-Ti phase transformation took place until 50 h. The results suggest that the addition of Ta and Sn promotes the fcc-Ti phase formation, obtaining 100% of this phase at 50 h onwards, whereas Nb and Mn show the opposite effect. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

12 pages, 4661 KiB  
Article
Preparation of Bulk TiZrNbMoV and NbTiAlTaV High-Entropy Alloys by Powder Sintering
by Yaqi Wu, Peter K. Liaw and Yong Zhang
Metals 2021, 11(11), 1748; https://doi.org/10.3390/met11111748 - 31 Oct 2021
Cited by 23 | Viewed by 2628
Abstract
The refractory HEAs block material was prepared by powder sintering, using an equal atomic proportion of mixed TiZrNbMoV and NbTiAlTaV metal powder raw materials. The phase was analyzed, using an XRD. The microstructure of the specimen was observed, employing a scanning electron microscope, [...] Read more.
The refractory HEAs block material was prepared by powder sintering, using an equal atomic proportion of mixed TiZrNbMoV and NbTiAlTaV metal powder raw materials. The phase was analyzed, using an XRD. The microstructure of the specimen was observed, employing a scanning electron microscope, and the compressive strength of the specimen was measured, using an electronic universal testing machine. The results showed that the bulk cubic alloy structure was obtained by sintering at 1300 °C and 30 MPa for 4 h, and a small amount of complex metal compounds were contained. According to the pore distribution, the formed microstructure can be divided into dense and porous zones. At a compression rate of 10−4s1, the yield strengths of TiZrNbMoV and NbTiAlTaV alloys are 1201 and 700 MPa, respectively. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

17 pages, 5453 KiB  
Article
Wear Dry Behavior of the Al-6061-Al2O3 Composite Synthesized by Mechanical Alloying
by Víctor Hugo Mercado-Lemus, Cynthia Daisy Gomez-Esparza, Juan Carlos Díaz-Guillén, Jan Mayén-Chaires, Adriana Gallegos-Melgar, Hugo Arcos-Gutierrez, Maricruz Hernández-Hernández, Isaías Emmanuel Garduño, José Antonio Betancourt-Cantera and Raúl Perez-Bustamante
Metals 2021, 11(10), 1652; https://doi.org/10.3390/met11101652 - 18 Oct 2021
Cited by 8 | Viewed by 2271
Abstract
The present research deals with the comparative wear behavior of a mechanically milled Al-6061 alloy and the same alloy reinforced with 5 wt.% of Al2O3 nanoparticles (Al-6061-Al2O3) under different dry sliding conditions. For this purpose, an [...] Read more.
The present research deals with the comparative wear behavior of a mechanically milled Al-6061 alloy and the same alloy reinforced with 5 wt.% of Al2O3 nanoparticles (Al-6061-Al2O3) under different dry sliding conditions. For this purpose, an aluminum-silicon-based material was synthesized by high-energy mechanical alloying, cold consolidated, and sintered under pressureless and vacuum conditions. The mechanical behavior was evaluated by sliding wear and microhardness tests. The structural characterization was carried out by X-ray diffraction and scanning electron microscopy. Results showed a clear wear resistance improvement in the aluminum matrix composite (Al-6061-Al2O3) in comparison with the Al-6061 alloy since nanoparticles act as a third hard body against wear. This behavior is attributed to the significant increment in hardness on the reinforced material, whose strengthening mechanisms mainly lie in a nanometric size and homogeneous dispersion of particles offering an effective load transfer from the matrix to the reinforcement. Discussion of the wear performance was in terms of a protective thin film oxide formation, where protective behavior decreases as a function of the sliding speed. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

16 pages, 5393 KiB  
Article
Formation and Properties of Oxide Coatings with Immobilized Zeolites Obtained by Plasma Electrolytic Oxidation of Aluminum
by Kristina Mojsilović, Uroš Lačnjevac, Srna Stojanović, Ljiljana Damjanović-Vasilić, Stevan Stojadinović and Rastko Vasilić
Metals 2021, 11(8), 1241; https://doi.org/10.3390/met11081241 - 5 Aug 2021
Cited by 6 | Viewed by 1713
Abstract
In this paper, we employed plasma electrolytic oxidation (PEO) of aluminum in a water solution of sodium tungstate (Na2WO4∙2H2O) with the addition of the pure and Ce-loaded zeolites clinoptilolite and 13 X for the preparation of oxide [...] Read more.
In this paper, we employed plasma electrolytic oxidation (PEO) of aluminum in a water solution of sodium tungstate (Na2WO4∙2H2O) with the addition of the pure and Ce-loaded zeolites clinoptilolite and 13 X for the preparation of oxide coatings. The obtained coatings were characterized with respect to their morphologies and chemical and phase compositions using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, atomic force microscopy, and X-ray diffraction. The prepared coatings contained γ-alumina, WO3, and metallic tungsten. The surface morphologies of the obtained coatings strongly depended on the PEO processing time; the roughness of all coatings increased with PEO time, while porosity decreased with PEO processing time as a result of microdischarge coalescence and growth. All coatings contained elements originating from the substrate and from the electrolytes. Coatings containing zeolites with Ce showed higher photoactivity than those with immobilized pure zeolites. The highest photocatalytic activity levels were observed for coatings containing immobilized Ce-exchanged clinoptilolite processed for 10 min. It was observed that both clinoptilolite and 13X zeolites improved the features of the PEO coatings in a similar manner, making natural and abundant clinoptilolite an excellent candidate for various applications. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Graphical abstract

16 pages, 5815 KiB  
Article
Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling
by Cristina García-Garrido, Ranier Sepúlveda Ferrer, Christopher Salvo, Lucía García-Domínguez, Luis Pérez-Pozo, Pedro Javier Lloreda-Jurado and Ernesto Chicardi
Metals 2021, 11(8), 1225; https://doi.org/10.3390/met11081225 - 31 Jul 2021
Cited by 5 | Viewed by 2237
Abstract
In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D [...] Read more.
In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

13 pages, 3396 KiB  
Article
Enhanced Permeability of Fe-Based Amorphous Powder Cores Realized through Selective Incorporation of Carbonyl Iron Powders at Inter-Particle Voids
by Hea-Ran Kim, Min-Sun Jang, Yeong-Gyun Nam, Yun-Seok Kim, Sang-Sun Yang, Yong-Jin Kim and Jae-Won Jeong
Metals 2021, 11(8), 1220; https://doi.org/10.3390/met11081220 - 30 Jul 2021
Cited by 15 | Viewed by 2889
Abstract
In this study, we demonstrate a hybrid multimodal soft magnetic composite (SMC) comprising gas-atomized spherical amorphous powder (AP) and carbonyl-iron powder (CIP), and present its enhanced electromagnetic properties. CIP is selectively incorporated into voids between AP, and deforms during compression, effectively reducing the [...] Read more.
In this study, we demonstrate a hybrid multimodal soft magnetic composite (SMC) comprising gas-atomized spherical amorphous powder (AP) and carbonyl-iron powder (CIP), and present its enhanced electromagnetic properties. CIP is selectively incorporated into voids between AP, and deforms during compression, effectively reducing the pores, resulting in high packing density of the core, where CIP magnetically bridges AP and helps magnetic domain rotation much efficiently. The hybrid SMC with the addition of 20 wt.% CIP showed constant effective permeability of 57 up to 1 MHz, a remarkable 63% increase compared with the AP core, while DC bias superimposing retention level of 61% was secured with the help of high magnetization of CIP. In addition, the effect of SiO2 surface insulation, prepared by the sol-gel process, on the high-frequency magnetic properties of hybrid SMCs, was also evaluated. It is thus revealed that the high-frequency dynamic loss of the hybrid core, originating from intra-particle eddy current loss and anomalous loss component, and inter-particle eddy currents are negligibly small. We believe that our approach using AP/CIP multimodal hybrid SMCs is an effective way of achieving high permeability as well as high DC bias characteristics at high frequencies. This process will be highly beneficial for the miniaturization of power inductors. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

17 pages, 3915 KiB  
Article
Influence of Chromium Concentration on the Abrasive Wear of Ni-Cr-B-Si Coatings Applied by Supersonic Flame Jet (HVOF)
by Mara Kandeva, Zhetcho Kalitchin and Yana Stoyanova
Metals 2021, 11(6), 915; https://doi.org/10.3390/met11060915 - 4 Jun 2021
Cited by 12 | Viewed by 2172
Abstract
This research work studies the characteristics of wear and wear resistance of composite powder coatings, deposited by supersonic flame jet (HVOF), which contain composite mixtures Ni-Cr-B-Si having different chromium concentrations—9.9%, 13.2%, 14%, 16%, and 20%, at one and the same size of the [...] Read more.
This research work studies the characteristics of wear and wear resistance of composite powder coatings, deposited by supersonic flame jet (HVOF), which contain composite mixtures Ni-Cr-B-Si having different chromium concentrations—9.9%, 13.2%, 14%, 16%, and 20%, at one and the same size of the particles and the same content of the remaining elements. The coating of 20% Cr does not contain B and Si. Out of each powder composite, coatings have been prepared without any preliminary thermal treatment of the substrate and with preliminary thermal treatment of the substrate up to 650 °C. The coatings have been tested under identical conditions of dry friction over a surface of solid, firmly-attached, abrasive particles using tribological testing device “Pin-on-disk”. Results have been obtained and the dependences of the hardness, mass wear, intensity of the wearing process, and absolute and relative wear resistance on the Cr concentration under identical conditions of friction. It has been found out that for all the coatings the preliminary thermal treatment of the substrate leads to a decrease in the wear intensity. Upon increasing Cr concentration the wear intensity diminishes and it reaches minimal values at 16% Cr. In the case of coatings having 20% Cr concentration, the wear intensity is increased, which is due to the absence of the components B and Si in the composite mixture, whereupon no inter-metallic structures are formed having high hardness and wear resistance. The obtained results have no analogues in the current literature and they have not been published by the authors. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

Review

Jump to: Research

23 pages, 7806 KiB  
Review
Recent Progress with BCC-Structured High-Entropy Alloys
by Fangfei Liu, Peter K. Liaw and Yong Zhang
Metals 2022, 12(3), 501; https://doi.org/10.3390/met12030501 - 16 Mar 2022
Cited by 35 | Viewed by 7441
Abstract
High-entropy alloys (HEAs) prefer to form single-phase solid solutions (body-centered cubic (BCC), face-centered cubic (FCC), or hexagonal closed-packed (HCP)) due to their high mixing entropy. In this paper, we systematically review the mechanical behaviors and properties (such as oxidation and corrosion) of BCC-structured [...] Read more.
High-entropy alloys (HEAs) prefer to form single-phase solid solutions (body-centered cubic (BCC), face-centered cubic (FCC), or hexagonal closed-packed (HCP)) due to their high mixing entropy. In this paper, we systematically review the mechanical behaviors and properties (such as oxidation and corrosion) of BCC-structured HEAs. The mechanical properties at room temperature and high temperatures of samples prepared by different processes (including vacuum arc-melting, powder sintering and additive manufacturing) are compared, and the effect of alloying on the mechanical properties is analyzed. In addition, the effects of HEA preparation and compositional regulation on corrosion resistance, and the application of high-throughput techniques in the field of HEAs, are discussed. To conclude, alloy development for BCC-structured HEAs is summarized. Full article
(This article belongs to the Special Issue Amorphous and High-Entropy Alloy Coatings)
Show Figures

Figure 1

Back to TopTop