Materials

Research

18 pages, 4662 KiB

Open AccessArticle

Preliminary Study on Electrochemical Deposition of Graphene on Steel Substrate via In Situ Oxidation Using Cyclic Voltammetry

by Mattia Pelucchi, Brigida Alfano, Giuseppe Cesare Lama, Raphael Palucci Rosa and Marina Cabrini

Materials 2025, 18(11), 2440; https://doi.org/10.3390/ma18112440 - 23 May 2025

Viewed by 196

Abstract

This study explores an innovative method for depositing graphene directly onto metal surfaces, using cyclic voltammetry with a suspension of graphene in water. Most electrochemical deposition techniques up to now have concentrated on graphene oxide (GO) rather than pure graphene, largely because GO [...] Read more.

This study explores an innovative method for depositing graphene directly onto metal surfaces, using cyclic voltammetry with a suspension of graphene in water. Most electrochemical deposition techniques up to now have concentrated on graphene oxide (GO) rather than pure graphene, largely because GO disperses more readily in water. This characteristic makes GO simpler to manipulate and apply in deposition processes, giving it an advantage in terms of usability and practicality. We demonstrated that graphene can indeed be deposited onto metal surfaces using this innovative electrochemical approach. We conducted a thorough characterization of the resulting graphene deposits, employing advanced techniques, including interferometric microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. These analyses provided us with insights into the structural, chemical, and morphological characteristics of the graphene deposits. This comparison allowed us to assess the strengths and potential improvements needed for this direct deposition method, as it offers a more sustainable and streamlined alternative to conventional GO-based processes. One important finding is that, while the quality of these direct graphene deposits has not yet reached the level of GO-based coatings, this new approach has some compelling advantages. Specifically, it is a simpler, more environmentally friendly process that could streamline production and reduce the environmental impact compared to traditional methods using GO. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

17 pages, 8086 KiB

Open AccessArticle

Effect of Al on the Oxidation Behavior of TiCrZrNbTa High-Entropy Coatings on Zr Alloy

by Min Guo, Chaoyang Chen, Bin Song, Junhong Guo, Junhua Hu and Guoqin Cao

Materials 2025, 18(9), 1997; https://doi.org/10.3390/ma18091997 - 28 Apr 2025

Viewed by 287

Abstract

This study investigates the role of Al alloying in tailoring the oxidation resistance of AlTiCrZrNbTa refractory high-entropy alloy (RHEA) coatings on Zry-4 substrates under high-temperature steam environments. Coatings with varying Al contents (0–25 at.%) were deposited via magnetron sputtering and subjected to oxidation [...] Read more.

This study investigates the role of Al alloying in tailoring the oxidation resistance of AlTiCrZrNbTa refractory high-entropy alloy (RHEA) coatings on Zry-4 substrates under high-temperature steam environments. Coatings with varying Al contents (0–25 at.%) were deposited via magnetron sputtering and subjected to oxidation tests at 1000–1100 °C. The results demonstrate that Al content critically governs oxidation kinetics and coating integrity. The optimal performance was achieved at 10 at.% Al, above which a dense, continuous composite oxide layer (Al₂O₃, TiO₂, Cr₂O₃) formed, effectively suppressing oxygen penetration and maintaining strong interfacial adhesion. Indentation tests confirmed enhanced mechanical integrity in Al-10 coatings, with minimal cracking post-oxidation. Excessive Al alloying (≥17 at.%) led to accelerated coating oxidation. This work establishes a critical Al threshold for balancing oxidation and interfacial bonding, providing a design strategy for developing accident-tolerant fuel cladding coatings. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

15 pages, 14093 KiB

Open AccessArticle

Effect of Si Addition on Structure and Corrosion Resistance of FeCoNiCr High-Entropy Alloy Coating

by Wenqiang Li, Jie Lian, Dengfeng Wang, Suo Zhang, Chengfu Han, Zhenyu Du and Fushan Li

Materials 2025, 18(1), 72; https://doi.org/10.3390/ma18010072 - 27 Dec 2024

Viewed by 753

Abstract

In this study, Fe₆₀Co_10−xNi₁₅Cr₁₅Si_x (x = 0, 4, and 8) powders were successfully prepared using the aerosol method and employed to produce high-entropy coatings on Q235 steel via laser cladding. The microstructure and phase [...] Read more.

In this study, Fe₆₀Co_10−xNi₁₅Cr₁₅Si_x (x = 0, 4, and 8) powders were successfully prepared using the aerosol method and employed to produce high-entropy coatings on Q235 steel via laser cladding. The microstructure and phase composition of the coatings were analyzed using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Corrosion resistance and potential were evaluated through electrochemical analysis and Kelvin probe force microscopy. The results show that the Fe₆₀Co_10−xNi₁₅Cr₁₅Si_x coatings exhibit excellent metallurgical bonding with no visible porosity or cracks. The coating primarily consists of an FCC structure; however, as the Si content increases, the structure transitions to a mixed FCC + BCC phase. The addition of Si also refines the grain size in the alloy system. Electrochemical analysis reveals that the Si0 and Si4 coatings exhibit similar corrosion behavior, while the Si8 coating shows a significant drop in corrosion potential, reducing its corrosion resistance. As the Si content increases, grain refinement leads to more grain boundaries, but the corrosion resistance decreases due to the lower corrosion performance of Si compared to Co. Considering both cost and corrosion resistance, the Si4 coating offers a balance of low cost and excellent corrosion resistance. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

19 pages, 8834 KiB

Open AccessEditor’s ChoiceArticle

Protective Properties of Silane Composite Coatings Modified with Poly(3,4-ethylenedioxythiophene) with Heteropolyacid on X20Cr13 and 41Cr4 Steel

by Aleksandra Kucharczyk-Kotlewska, Lidia Adamczyk, Krzysztof Miecznikowski and Agata Dudek

Materials 2024, 17(24), 6177; https://doi.org/10.3390/ma17246177 - 18 Dec 2024

Viewed by 568

Abstract

This paper describes the methodology of the preparation and analyses of the structure and anticorrosion properties of silane coatings modified with poly(3,4-ethylenedioxythiophene) (PEDOT) with phosphododecamolybdic acid (PMo₁₂). Protective coatings, consisting of vinyltrimethoxysilane (VTMS), PEDOT powder with PMo₁₂ admixture (at different [...] Read more.

This paper describes the methodology of the preparation and analyses of the structure and anticorrosion properties of silane coatings modified with poly(3,4-ethylenedioxythiophene) (PEDOT) with phosphododecamolybdic acid (PMo₁₂). Protective coatings, consisting of vinyltrimethoxysilane (VTMS), PEDOT powder with PMo₁₂ admixture (at different concentrations), and ethanol, were deposited on X20Cr13 and 41Cr4 steels by immersion. The physicochemical properties of these silane coatings (e.g., surface morphology, thickness, roughness, and adhesion to the substrate) were elucidated using a digital microscope, a Fourier transform infrared spectrophotometer with attenuated total reflectance, and various electrochemical diagnostic techniques. Protective properties were assessed in acidified sulfate solutions with and without chloride ions (pH 2). Experimental results have shown that this coating displayed the effective protection of steel against general and pitting corrosion, stabilized the corrosion potential in the passive state, and provided barrier protection. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

16 pages, 4681 KiB

Open AccessArticle

Preliminary Aspects Regarding the Anticorrosive Effect of Multi-Layered Silane–Hydroxyapatite Coatings Deposited on Titanium Grade 2 for Medical Applications

by Agata Dudek and Oliwia Kierat

Materials 2024, 17(23), 6001; https://doi.org/10.3390/ma17236001 - 7 Dec 2024

Cited by 1 | Viewed by 942

Abstract

This paper presents a method for producing VTMS/HAp/VTMS/VTMS multilayer coatings on a Grade 2 titanium substrate and characterizes their structure and functional properties. Two solutions were used to produce the coatings: one based on vinyltrimethoxysilane (VTMS) and the other on hydroxyapatite (HAp) powder. [...] Read more.

This paper presents a method for producing VTMS/HAp/VTMS/VTMS multilayer coatings on a Grade 2 titanium substrate and characterizes their structure and functional properties. Two solutions were used to produce the coatings: one based on vinyltrimethoxysilane (VTMS) and the other on hydroxyapatite (HAp) powder. The coatings were applied using immersion using the sol-gel method. Microstructural tests of the multilayer coatings were performed, their chemical composition was determined, and the structure was characterized using Fourier Transform Infrared Spectroscopy (FTIR). A detailed analysis of the geometric structure of the coatings was carried out both before and after corrosion tests. The geometric structure of the multilayer coatings was analyzed using a light microscope and an atomic force microscope (AFM). The thickness of the coatings was determined using a Testan DT-10 AN 120 157 m, and the adhesion of the coatings to the substrate was analyzed using Scotch™ tape. The corrosion resistance of the coatings in simulated body fluid was tested to evaluate their suitability for implantology. As demonstrated by the research presented in this paper, the sol–gel process can successfully produce silane coatings by adding hydroxyapatite powder. The new materials proposed in this study can effectively protect metal materials used in medicine against corrosion. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

13 pages, 5598 KiB

Open AccessArticle

Synthesis of Amphiphilic Polyacrylates as Peelable Coatings for Optical Surface Cleaning

by Daofeng Zhu, Hao Huang, Anqi Liang, Yanling Yang, Baohan He, Abbas Ahmed, Xiaoyan Li, Fuchuan Ding and Luyi Sun

Materials 2024, 17(19), 4813; https://doi.org/10.3390/ma17194813 - 30 Sep 2024

Viewed by 998

Abstract

Optical instruments require extremely high precision, and even minor surface contamination can severely impact their performance. Peelable coatings offer an effective and non-damaging method for removing contaminants from optical surfaces. In this study, an amphiphilic polyacrylate copolymer (PMLEA) was synthesized via solution radical [...] Read more.

Optical instruments require extremely high precision, and even minor surface contamination can severely impact their performance. Peelable coatings offer an effective and non-damaging method for removing contaminants from optical surfaces. In this study, an amphiphilic polyacrylate copolymer (PMLEA) was synthesized via solution radical copolymerization using the lipophilic monomer lauryl acrylate (LA) and hydrophilic monomers ER-10, methyl methacrylate (MMA), and butyl acrylate (BA). The structure and molecular weight of the copolymer were characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The hydrophilic–lipophilic balance, surface tension, and wettability of the copolymer were analyzed through water titration, the platinum plate method, and liquid contact angle tests. The cleaning performance of the copolymer coating on quartz glass surface contaminants was evaluated using optical microscopy and Ultraviolet-Visible Near-Infrared (UV-Vis-NIR) spectroscopy. The study examined the effect of varying the ratio of LA to ER-10 on the hydrophilicity, lipophilicity, cleaning efficiency, and mechanical properties of the copolymer coating. The results showed that when the mass ratio of LA to ER-10 was 1:2, the synthesized copolymer exhibited optimal performance in removing dust, grease, and fingerprints from quartz glass surfaces. The coating had a tensile strength of 2.57 MPa, an elongation at break of 183%, and a peeling force of 2.07 N m⁻¹. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

13 pages, 4551 KiB

Open AccessArticle

Effect of N₂/Ar Ratio on Wear Behavior of Multi-Element Nitride Coatings on AISI H13 Tool Steel

by Cheng-Hsun Hsu, Hong-Wei Chen, Chun-Yin Lin and Syue-Hong Hu

Materials 2024, 17(19), 4748; https://doi.org/10.3390/ma17194748 - 27 Sep 2024

Cited by 1 | Viewed by 847

Abstract

In this study, multi-element nitride coatings composed of (Ti, Cr, Cu, Al, Si)N were synthesized on H13 tool steel using cathodic arc deposition (CAD) technology. The N₂/Ar flow ratio varied from 0 to 2 as the experimental parameter, and two targets, [...] Read more.

In this study, multi-element nitride coatings composed of (Ti, Cr, Cu, Al, Si)N were synthesized on H13 tool steel using cathodic arc deposition (CAD) technology. The N₂/Ar flow ratio varied from 0 to 2 as the experimental parameter, and two targets, Ti-Cr-Cu and Al-Si alloys, were utilized simultaneously. The impact of the gas flow ratio on the coatings’ abrasion properties was investigated, focusing on aspects, such as chemical composition, adhesion, hardness, and wear behavior. The experimental findings indicate that the coated specimens with a nitrogen reaction exhibit superior hardness and abrasion resistance compared to those without nitrogen use. While the surface roughness of the specimens tends to increase slightly with a higher N2/Ar ratio, the coating demonstrates improved hardness, adhesion, and abrasion resistance performance. In summary, the wear-resistant characteristics of H13 tool steel can be significantly enhanced when applying a CAD-(Ti, Cr, Cu, Al, Si)N film with a flow ratio of N₂/Ar = 2. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

13 pages, 17643 KiB

Open AccessArticle

Zirconia and Crofer Joint Made by Reactive Air Brazing Using the Silver Base Paste and Cu-Ti Coating Layer

by Shu-Wei Chang, Ren-Kae Shiue and Liang-Wei Huang

Materials 2024, 17(15), 3822; https://doi.org/10.3390/ma17153822 - 2 Aug 2024

Cited by 1 | Viewed by 888

Abstract

This study proposes a method to enhance the airtightness of the joint between the ZrO₂ and Crofer alloy using coating technology. With the aid of vacuum sputtering technology, a titanium–copper alloy layer with a thickness between 1.5 μm and 6 μm was [...] Read more.

This study proposes a method to enhance the airtightness of the joint between the ZrO₂ and Crofer alloy using coating technology. With the aid of vacuum sputtering technology, a titanium–copper alloy layer with a thickness between 1.5 μm and 6 μm was first deposited on the surface of ZrO₂ and Crofer, respectively. The chemical composition of the deposited reaction layer was 70.2 Cu and 29.8 Ti in at%. Then, using silver as the base material in the reactive air brazing (RAB) process, we explore the use of this material design to improve the microstructure and reaction mechanism of the joint surface between ceramics and metal, compare the effects of different pretreatment thicknesses on the microstructure, and evaluate its effectiveness through air tightness tests. The results show that a coating of Cu-Ti alloy on the ZrO₂ substrate can significantly improve bonding between the Ag filler and ZrO₂. The Cu-Ti metallization layer on the ZrO₂ substrate is beneficial to the RAB. After the brazing process, the coated Cu-Ti layers form suitable reaction interfaces between the filler, the metal, the filler, and the ceramic. In terms of coating layer thickness, the optimized 3 μm coated Cu-Ti alloy layer is achieved from the experiment. Melting and dissolving the Cu-Ti coated layer into the ZrO₂ substrate results in a defect-free interface between the Ag-rich braze and the ZrO₂. The air tightness test result shows no leakage under 2 psig at room temperature for 28 h. The pressure condition can still be maintained even under high-temperature conditions of 600 °C for 24 h. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

14 pages, 6045 KiB

Open AccessArticle

Electrical Conductivity and Antibacterial Activity of Woven Fabrics through Quercetin-Assisted Thermal Reduction of a Graphene Oxide Coating

by Mariia Svyntkivska, Tomasz Makowski, Dorota Kregiel and Ewa Piorkowska

Materials 2023, 16(22), 7184; https://doi.org/10.3390/ma16227184 - 16 Nov 2023

Viewed by 1488

Abstract

Cotton and poly(ethylene terephthalate) (PET) woven fabrics were coated with graphene oxide (GO) using a padding method and the GO deposited on the fiber surfaces was thermally reduced to impart electrical conductivity to the fabrics. To assist the thermal reduction of GO, quercetin [...] Read more.

Cotton and poly(ethylene terephthalate) (PET) woven fabrics were coated with graphene oxide (GO) using a padding method and the GO deposited on the fiber surfaces was thermally reduced to impart electrical conductivity to the fabrics. To assist the thermal reduction of GO, quercetin (Q)—a natural flavonoid—was used. To this end, before the reduction, the GO-padded fabrics were immersed in Q solutions in ethanol with different Q concentrations. Q enhanced the thermal reduction of GO. Depending on the Q concentration in the solutions, electrical surface resistivities of the cotton fabric of 750 kΩ/sq to 3.3 MΩ/sq and of the PET fabric of 240 kΩ/sq to 730 kΩ/sq were achieved. The cotton and PET fabrics also became hydrophobic, with water contact angles of 163° and 147°, respectively. In addition to the electrical conductivity, the presence of Q resulted in antibacterial activity of the fabrics against Escherichia coli and Staphylococcus aureus. Full article

(This article belongs to the Special Issue Fabrication and Properties of Functional Coatings Under Extreme Conditions)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Fabrication and Properties of Functional Coatings Under Extreme Conditions

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (9 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI