Sustainable Coatings on Metallic Alloys as a Nowadays Challenge

Starting with a description of the meaning of sustainable coating nowadays, this review presents a selection of methods for sustainable coatings manufacture using raw materials, saving energy and costs. This selection creates an introduction for the coatings performances of intensively investigated coated alloys and their multifunctionality. There are many examples and EU recommendations to be discussed, and we especially chose to introduce sustainable coatings with both industrial and medical functions, such as bioinspired films and coatings on high-entropy alloys, biodegradable metallic alloys, etc. A special focus is on nanotechnology and nanomaterials in green procedures, enhancing coatings’ multifunctionality, introducing green corrosion inhibitors, smart additives, and coatings based on superhydrophobicity. The conclusions and future perspectives of sustainable and multifunctional coatings, as expressions of sustainable advanced materials, are based on important motivations of such studies.

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Preparation of Bulk TiZrNbMoV and NbTiAlTaV High-Entropy Alloys by Powder Sintering

Metals ◽

10.3390/met11111748 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1748

Author(s):

Yaqi Wu ◽

Peter K. Liaw ◽

Yong Zhang

Keyword(s):

Raw Materials ◽

Testing Machine ◽

Compression Rate ◽

High Entropy Alloys ◽

Alloy Structure ◽

Metal Compounds ◽

High Entropy ◽

Universal Testing ◽

Powder Sintering ◽

Scanning Electron

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 10−4s−1, the yield strengths of TiZrNbMoV and NbTiAlTaV alloys are 1201 and 700 MPa, respectively.

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Organic Green Corrosion Inhibitors Derived from Natural and/or Biological Sources for Conservation of Metals Cultural Heritage

Microorganisms in the Deterioration and Preservation of Cultural Heritage ◽

10.1007/978-3-030-69411-1_15 ◽

2021 ◽

pp. 341-367

Author(s):

Vasilike Argyropoulos ◽

Stamatis C. Boyatzis ◽

Maria Giannoulaki ◽

Elodie Guilminot ◽

Aggeliki Zacharopoulou

Keyword(s):

Cultural Heritage ◽

Corrosion Inhibitors ◽

Electrochemical Techniques ◽

Extraction Process ◽

Special Focus ◽

Green Inhibitor ◽

Biological Sources ◽

Art Research ◽

Green Corrosion Inhibitors

AbstractIn the last decade, there has been an increase in research related to green corrosion inhibitors for conservation of metals cultural heritage to help promote sustainable practices in the field that are safe, environmentally friendly, and ecologically acceptable. The most common are organic substances derived either from natural and/or biological sources: plant extracts and oils, amino acids, microorganisms, and biopolymers. The chapter will provide a review of these substances as corrosion inhibitors for metals conservation, by discussing the state-of-the-art research to date, with a special focus on cysteine. Most of the research has focused on the examination of such inhibitors on metal coupons with or without corrosion products using electrochemical techniques or weight-loss measurements to determine their effectiveness. Some of these studies have also considered the conservation principles for practice, i.e., reversibility of the treatment and the visual aspect of the modification of the treated metal surface. However, before such green inhibitors can be routinely applied by conservators, more research is required on their application to real artefacts/monuments using in situ corrosion measurements. Furthermore, given that the composition of a green inhibitor is highly dependent on its extraction process, research must also involve identifying the specific adsorption models and involved mechanisms to ensure reproducibility of results.

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The Microstructures and Electrical Resistivity of (Al, Cr, Ti)FeCoNiOxHigh-Entropy Alloy Oxide Thin Films

Advances in Materials Science and Engineering ◽

10.1155/2015/353140 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

Chun-Huei Tsau ◽

Zhang-Yan Hwang ◽

Swe-Kai Chen

Keyword(s):

Thin Films ◽

Oxide Films ◽

Annealing Treatment ◽

Metallic Alloys ◽

Vacuum Furnace ◽

High Entropy Alloys ◽

Oxide Thin Films ◽

Metal Oxide Films ◽

High Entropy ◽

Feconi Alloy

The (Al, Cr, Ti)FeCoNi alloy thin films were deposited by PVD and using the equimolar targets with same compositions from the concept of high-entropy alloys. The thin films became metal oxide films after annealing at vacuum furnace for a period; and the resistivity of these thin films decreased sharply. After optimum annealing treatment, the lowest resistivity of the FeCoNiOx, CrFeCoNiOx, AlFeCoNiOx, and TiFeCoNiOxfilms was 22, 42, 18, and 35 μΩ-cm, respectively. This value is close to that of most of the metallic alloys. This phenomenon was caused by delaminating of the alloy oxide thin films because the oxidation was from the surfaces of the thin films. The low resistivity of these oxide films was contributed to the nonfully oxidized elements in the bottom layers and also vanishing of the defects during annealing.

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Microstructural Characterization and Mechanical Properties of Laser Deposited High Entropy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2370 ◽

2014 ◽

Vol 783-786 ◽

pp. 2370-2375

Author(s):

Harihar Sistla ◽

Joseph W. Newkirk ◽

F. Frank Liou

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Microstructural Characterization ◽

Alloy System ◽

Lattice Parameter ◽

Laser Deposition ◽

Advanced Materials ◽

Mechanical And Thermal Properties ◽

High Entropy Alloys ◽

High Entropy

High entropy alloys have attracted great interest due to their flexibility in composition accompanied with very interesting properties, which make these materials candidates for further research. The formation of single solid solution phases as a preference to complex mixtures of intermetallic phases leads to good mechanical and thermal properties. Additive manufacturing in the form of Laser deposition presents us with a very unique way to manufacture near net shape metallic components with advanced materials. The present study focusses on the characterization of High entropy alloys manufactured through laser deposition. The alloy system considered for this study is (AlFeCoCrNi). The ratio of aluminum to nickel was decreased to observe the transition of the solid solution from a BCC structure to a FCC structure. The lattice parameter increased from .288 nm to .357 nm and the hardness decreased from Hv 670 to Hv 149 respectively. The effect of composition on thermodynamic variables, microstructure and mechanical properties were analyzed.

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Revealing the Selection of σ and μ Phases in CoCrFeNiMox High Entropy Alloys by CALPHAD

Journal of Phase Equilibria and Diffusion ◽

10.1007/s11669-018-0659-7 ◽

2018 ◽

Vol 39 (4) ◽

pp. 446-453 ◽

Cited By ~ 10

Author(s):

Qingfeng Wu ◽

Zhijun Wang ◽

Feng He ◽

Junjie Li ◽

Jincheng Wang

Keyword(s):

High Entropy Alloys ◽

High Entropy ◽

Selection Of

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Evaluation of Green Inhibitors

4th International Pipeline Conference, Parts A and B ◽

10.1115/ipc2002-27335 ◽

2002 ◽

Author(s):

Sankara Papavinasam ◽

Alex Doiron ◽

R. Winston Revie

Keyword(s):

Environmental Effects ◽

Corrosion Inhibitors ◽

Test Methods ◽

Offshore Pipelines ◽

Internal Corrosion ◽

Green Inhibitors ◽

Current Test ◽

The World ◽

Green Corrosion Inhibitors ◽

Selection Of

Producing pipelines are protected from internal corrosion by the application of corrosion inhibitors. Environmental effects of corrosion inhibitors have received increased attention in recent years, especially for offshore pipelines. In response to the drive for more environmentally friendly inhibitors, several “green” corrosion inhibitors have been developed. In the design of new classes of corrosion inhibitors, there is a need to take into account the various environmental regulations that exist. In this paper, the criteria for selecting green inhibitors as used in various part of the world are reviewed. The current test methods, their reproducibility and effectiveness, and their accuracy in relation to the selection of green inhibitors are discussed.

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High Entropy Alloys: Ready to Set Sail?

Metals ◽

10.3390/met10020194 ◽

2020 ◽

Vol 10 (2) ◽

pp. 194 ◽

Cited By ~ 1

Author(s):

Indranil Basu ◽

Jeff Th. M. De Hosson

Keyword(s):

Mechanical Response ◽

High Surface ◽

Volume Ratio ◽

Material Design ◽

Point Of View ◽

Advanced Materials ◽

High Entropy Alloys ◽

High Entropy ◽

Material Development ◽

Structural And Functional Properties

Over the past decade, high entropy alloys (HEAs) have transcended the frontiers of material development in terms of their unprecedented structural and functional properties compared to their counterpart conventional alloys. The possibility to explore a vast compositional space further renders this area of research extremely promising in the near future for discovering society-changing materials. The introduction of HEAs has also brought forth a paradigm shift in the existing knowledge about material design and development. It is in this regard that a fundamental understanding of the metal physics of these alloys is critical in propelling mechanism-based HEA design. The current paper highlights some of the critical viewpoints that need greater attention in the future with respect to designing mechanically and functionally advanced materials. In particular, the interplay of large compositional gradients and defect topologies in these alloys and their corresponding impact on overall mechanical response are highlighted. From the point of view of functional response, such chemistry vis-à-vis topology correlations are extended to novel class of nano-porous HEAs that beat thermal coarsening effects despite a high surface to volume ratio owing to retarded diffusion kinetics. Recommendations on material design with regards to their potential use in diverse applications such as energy storage, actuators, and as piezoelectrics are additionally considered.

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Selection of High Entropy Alloy for Solid Solution Using Multi-Criteria Decision Making Tool

Materials Science Forum ◽

10.4028/www.scientific.net/msf.969.466 ◽

2019 ◽

Vol 969 ◽

pp. 466-471

Author(s):

Vinay Kumar Soni ◽

Shubhashis Sanyal ◽

Sudip Kumar Sinha

Keyword(s):

Solid Solution ◽

Vital Role ◽

Size Difference ◽

High Entropy Alloy ◽

High Entropy Alloys ◽

High Entropy ◽

Atomic Size Difference ◽

Topological Parameter ◽

Topsis Technique ◽

Selection Of

High entropy alloys (HEA’s) have found a very special place in aerospace industries due to their property of forming solid solution. In past literatures on high entropy alloys, it is established that parameters like atomic size difference (), topological parameter (Ω) and electro-negativity difference (∆) plays a vital role in deciding whether solid solution will be formed or not. Therefore, the present study deals with the selection of optimal high entropy composition based on the three parameters δ, Ω and with the help of TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution). Ranking is done for 38 HEA different compositions such that the first rank represents the HEA which is most likely to form solid solution. The study reveals that TOPSIS method can be successfully implemented to predict the formation of solid solution in HEA’s.

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An Overview of High-Entropy Alloys as Biomaterials

Metals ◽

10.3390/met11040648 ◽

2021 ◽

Vol 11 (4) ◽

pp. 648

Author(s):

Diogo Castro ◽

Pedro Jaeger ◽

Ana Catarina Baptista ◽

João Pedro Oliveira

Keyword(s):

Literature Review ◽

Biomedical Applications ◽

Design Approach ◽

Special Focus ◽

High Entropy Alloys ◽

Biomedical Materials ◽

High Entropy ◽

Short Overview ◽

Theoretical Design ◽

Potential Applications

High-entropy alloys (HEAs) have been around since 2004. The breakthroughs in this field led to several potential applications of these alloys as refractory, structural, functional, and biomedical materials. In this work, a short overview on the concept of high-entropy alloys is provided, as well as the theoretical design approach. The special focus of this review concerns one novel class of these alloys: biomedical high-entropy alloys. Here, a literature review on the potential high-entropy alloys for biomedical applications is presented. The characteristics that are required for these alloys to be used in biomedical-oriented applications, namely their mechanical and biocompatibility properties, are discussed and compared to commercially available Ti6Al4V. Different processing routes are also discussed.

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