Coatings

18 pages, 7349 KiB

Open AccessArticle

Recycling of Glass Waste by Deposition of TiO₂ for the Intensification of the Photocatalytic Effect in the Purification of Wastewater

by Gabriela Isopencu, Mihai Eftimie, Alina Melinescu, Annette Madelene Dancila and Monica Mares

Coatings 2022, 12(11), 1794; https://doi.org/10.3390/coatings12111794 - 21 Nov 2022

Viewed by 1579

Abstract

In this study, the photocatalytic effect of TiO₂ (1 wt. % and 3 wt. %) deposited on the surface of sintered cathode ray tube glass was examined, as well as its effect on an E. coli strain (BL21(DE3)). DTA analysis indicated the [...] Read more.

In this study, the photocatalytic effect of TiO₂ (1 wt. % and 3 wt. %) deposited on the surface of sintered cathode ray tube glass was examined, as well as its effect on an E. coli strain (BL21(DE3)). DTA analysis indicated the sintering temperature for samples to be 820 °C while scanning electron microscopy (SEM)showed an intimate contact and a strong interface between the support and photocatalyst. Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) was employed to establish the chemical and bonding environment of the samples. The investigations of the bacterial viability were conducted using flow cytometry, a specific cellular viability assay, while bacterial growth was measured using the turbidimetric method. The experimental results show the influence of the TiO₂ concentration on the bacterial inactivation process: higher concentrations (3% wt.) have a bactericidal effect in the long term, whereas lower concentrations (1% wt.) render them inactive for a shorter time in the exponential growth stage. The preliminary results were used to calculate the efficiency of microbial inactivation and the parameters of the kinetics of inactivation using ANOVA software. The results indicate that this material could be an effective solution for water disinfection. Full article

(This article belongs to the Special Issue Recent Advances in Antibacterial Composite Coatings)

► Show Figures

Graphical abstract

17 pages, 5924 KiB

Open AccessArticle

A Novel Protection Method for Carbonate Stone Artifacts with Gypsum Weathering Crusts

by Ruicong Lu, Lu He, Ting Li, Fuwei Yang, Yan Liu, Kun Zhang and Xinnan Chen

Coatings 2022, 12(11), 1793; https://doi.org/10.3390/coatings12111793 - 21 Nov 2022

Cited by 2 | Viewed by 2012

Abstract

An innovative method using a methanol solution of barium hydroxide-urea as a protective agent was investigated for the conservation of stone artifacts with harmful gypsum weathering crusts. In this method, the methanol solution of barium hydroxide-urea and water were introduced into the gypsum [...] Read more.

An innovative method using a methanol solution of barium hydroxide-urea as a protective agent was investigated for the conservation of stone artifacts with harmful gypsum weathering crusts. In this method, the methanol solution of barium hydroxide-urea and water were introduced into the gypsum crust in sequence by surface spraying. By doing so, the harmful gypsum crust is directly converted into a barium sulfate—calcium carbonate composite protective layer. The properties of the composite layer were characterized by SEM-EDX, XRD, ATR-FTIR, IC, water solubility, wetting angle, color difference, open porosity, capillary water absorption, and surface hardness. The results of the morphological and composition characterization (SEM-EDX, XRD, ATR-FTIR) indicate that the added urea can promote the carbonization reaction effectively. In addition, the methanol solution of barium hydroxide-urea can penetrate deep into the gypsum crust. The results of the physical properties characterization denote that the water stability of the specimens was significantly increased after the protection treatment; an approximate ten-fold stronger water resistance ability was achieved. Meanwhile, the intrinsic physical properties of gypsum crust, such as pore structure and original appearance, could basically be maintained. The presented conservative method has high facility and controllability and satisfying conservation effect, which means it has potential in the conservation of surface weathering carbonate stone artifacts. Full article

(This article belongs to the Special Issue Advanced Coating Material for Heritage Preservation)

► Show Figures

Figure 1

11 pages, 4149 KiB

Open AccessArticle

Mechanical and Tribological Study on Aluminum Coatings with High-Pressure and Low-Pressure Cold-Spray Processes

by Abreeza Manap, NF Afandi, Savisha Mahalingam, Siti Nurul Akmal Yusof and Zulkifli Mohd. Rosli

Coatings 2022, 12(11), 1792; https://doi.org/10.3390/coatings12111792 - 21 Nov 2022

Cited by 3 | Viewed by 1608

Abstract

Cold spray is a promising approach to repair all damages and defects in aluminum (Al) constituent elements. The study aims to investigate the mechanical and tribological properties of Al coatings deposited using high-pressure cold-spray (HPCS) and low-pressure cold-spray (LPCS) techniques. Al powder was [...] Read more.

Cold spray is a promising approach to repair all damages and defects in aluminum (Al) constituent elements. The study aims to investigate the mechanical and tribological properties of Al coatings deposited using high-pressure cold-spray (HPCS) and low-pressure cold-spray (LPCS) techniques. Al powder was sprayed on a cold-rolled plate of aluminum 1100, which was used as the substrate. The results showed that the micro-hardness of the LPCS Al coating reached up to 196.6 HV before the wear test compared to that of HPCS (174.3 HV). Moreover, more low friction coefficients obtained by LPCS (0.798) than HPCS (0.807) indicated good tribological properties with a high amount of oxide composition. Meanwhile, the wear studies reveal that the specific wear rate of the Al coating of LPCS (0.008) was lower than the HPCS (0.009) as the load increased from 3 N to 5 N, thus providing excellent wear resistance. Therefore, the results exhibited greater mechanical and tribological characteristics for Al coatings produced by the LPCS process than by the HPCS process. Full article

(This article belongs to the Special Issue Advanced Cold Spraying Technology)

► Show Figures

Figure 1

14 pages, 380 KiB

Open AccessArticle

Effect of Resin Finishing on Some Properties of 100% Cotton Light Weight Woven Fabric

by Long-Yi Ho and Chi-Wai Kan

Coatings 2022, 12(11), 1791; https://doi.org/10.3390/coatings12111791 - 21 Nov 2022

Cited by 3 | Viewed by 2288

Abstract

In this study, experimental investigation was conducted to assess the wrinkle-resistance performance of resin-treated 100% cotton light-weight fabric. Resin (Dimethyloldihydroethylene urea, DMDHEU) was used for treating 100% cotton light-weight fabric with different treatment parameters (resin concentration: 30 g/L, 45 g/L, 60 g/L; pick-up: [...] Read more.

In this study, experimental investigation was conducted to assess the wrinkle-resistance performance of resin-treated 100% cotton light-weight fabric. Resin (Dimethyloldihydroethylene urea, DMDHEU) was used for treating 100% cotton light-weight fabric with different treatment parameters (resin concentration: 30 g/L, 45 g/L, 60 g/L; pick-up: 60%, 70%, 80%; drying temperature: 110 °C, 120 °C; and curing time: 2 min, 2.5 min, 3 min). After resin treatment, wrinkle properties, as well as the tearing strength and dimensional stability, of the resin treated fabrics were evaluated. Experimental results revealed that the resin concentration, pick-up, drying temperature, and curing time are inter-related, which could affect the final performance of the 100% cotton light-weight woven fabric. Thus, the effects of different parameters on the performance of the 100% cotton light-weight woven fabric were compared and discussed. Generally speaking, the resin finishing improved the wrinkle properties and dimensional stability but reduced the tearing strength of 100% cotton light-weight woven fabric. Full article

► Show Figures

Figure 1

22 pages, 2292 KiB

Open AccessReview

Nondestructive Testing Technologies for Rail Inspection: A Review

by Wendong Gong, Muhammad Firdaus Akbar, Ghassan Nihad Jawad, Mohamed Fauzi Packeer Mohamed and Mohd Nadhir Ab Wahab

Coatings 2022, 12(11), 1790; https://doi.org/10.3390/coatings12111790 - 21 Nov 2022

Cited by 16 | Viewed by 5796

Abstract

Alongside the development of high-speed rail, rail flaw detection is of great importance to ensure railway safety, especially for improving the speed and load of the train. Several conventional inspection methods such as visual, acoustic, and electromagnetic inspection have been introduced in the [...] Read more.

Alongside the development of high-speed rail, rail flaw detection is of great importance to ensure railway safety, especially for improving the speed and load of the train. Several conventional inspection methods such as visual, acoustic, and electromagnetic inspection have been introduced in the past. However, these methods have several challenges in terms of detection speed and accuracy. Combined inspection methods have emerged as a promising approach to overcome these limitations. Nondestructive testing (NDT) techniques in conjunction with artificial intelligence approaches have tremendous potential and viability because it is highly possible to improve the detection accuracy which has been proven in various conventional nondestructive testing techniques. With the development of information technology, communication technology, and sensor technology, rail health monitoring systems have been evolving, and have become equally significant and challenging because they can achieve real-time detection and give a risk warning forecast. This paper provides an in-depth review of traditional nondestructive techniques for rail inspection as well as the development of using machine learning approaches, combined nondestructive techniques, and rail health monitoring systems. Full article

(This article belongs to the Special Issue Nondestructive Evaluation of Material Surfaces: Theory, Techniques and Applications)

► Show Figures

Figure 1

11 pages, 2515 KiB

Open AccessArticle

Studies of Boriding Using Possibility to Increase the Corrosion Resistance of Cast Steel 20GL

by Alexey Mednikov, Alexander Tkhabisimov, Olga Kalakuckaya, Olga Zilova and Gennady Kachalin

Coatings 2022, 12(11), 1789; https://doi.org/10.3390/coatings12111789 - 21 Nov 2022

Viewed by 1348

Abstract

This paper presents the findings of corrosion studies of cast steel 20GL (structural alloyed steel: G—1% of Mn, L—alloyed) with boriding, selected as a promising passive method of protecting hydraulic machine elements from hydro-solid particle erosion and corrosive effects. Earlier studies have shown [...] Read more.

This paper presents the findings of corrosion studies of cast steel 20GL (structural alloyed steel: G—1% of Mn, L—alloyed) with boriding, selected as a promising passive method of protecting hydraulic machine elements from hydro-solid particle erosion and corrosive effects. Earlier studies have shown the boriding efficiency to increase the solid particle erosion resistance of cast steel 20GL by two–eight times depending on the solid particles’ impact angle of 30° and 90°. The boriding was carried out in a melt based on sodium tetraborate, sodium fluoride and sodium chloride salts in a shaft furnace with external heating. Results indicated that the boriding process did not affect the initial roughness of cast steel 20GL but increased the surface microhardness by more than six times, up to 1680–2080 HV0.01. The total layer thickness after two boriding processes was from 80 to 150 µm. The results of corrosion resistance studies by electrochemical methods obtained in this work showed the positive effect of boriding of steel 20GL. Boriding turns steel 20GL from a low-resistant class (score 6) to a resistant class (score 4–5) on a 10-point scale of corrosion resistance of metals. The boriding at a depth of 150 ± 5 µm reduces the corrosion rate in the environment of 3% NaCl solution by 2.8 times and in the environment of 0.7% Na₂SO₄ solution by 4.1 times, compared with the initial material without modification. It is revealed that an increase in boriding depth leads to an increase in corrosion resistance. The results indicate that the boriding of hydraulic machine parts made of 20GL steel will increase their corrosion resistance, thus prolonging the operating and overhaul period. Full article

(This article belongs to the Section Corrosion, Wear and Erosion)

► Show Figures

Figure 1

17 pages, 4281 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Insights into the Electrical Characterization of Graphene-like Materials from Carbon Black

by Raffaella Ferraiuolo, Michela Alfe, Valentina Gargiulo, Giovanni Piero Pepe, Francesco Tafuri, Alessandro Pezzella, Giovanni Ausanio and Domenico Montemurro

Coatings 2022, 12(11), 1788; https://doi.org/10.3390/coatings12111788 - 21 Nov 2022

Cited by 1 | Viewed by 2290

Abstract

A new class of graphene-related materials (GRMs) obtained as water suspensions through a two-step oxidation/reduction of a nanostructured carbon black, namely graphene-like (GL) materials, has recently emerged. GL materials undergo self-assembly in thin amorphous films after drying upon drop-casting deposition on different surfaces. [...] Read more.

A new class of graphene-related materials (GRMs) obtained as water suspensions through a two-step oxidation/reduction of a nanostructured carbon black, namely graphene-like (GL) materials, has recently emerged. GL materials undergo self-assembly in thin amorphous films after drying upon drop-casting deposition on different surfaces. The GL films, with thicknesses of less than a micron, were composed of clusters of nanoparticles each around 40 nm in size. The exploitation of the GL films for different options (e.g., bioelectronic, sensoristic, functional filler in composite) requires a deep characterization of the material in terms of their electric transport properties and their possible interaction with the surface on which they are deposited. In this work, a careful electrical characterization of GL films was performed at room temperature and the results were compared with those achieved on films of benchmark graphenic materials, namely graphene oxide (GO) materials, obtained by the exfoliation of graphite oxide, which differ both in morphology and in oxidation degree. The results indicate a non-linear current–voltage relationship for all the investigated films. The extrapolated dielectric constant (ε) values of the investigated GRMs (GL and GO materials) agree with the experimental and theoretically predicted values reported in the literature (ε~2–15). Because similar conductance values were obtained for the GL materials deposited on glass and silicon oxide substrates, no significant interactions of GL materials with the two different substrates were highlighted. These results are the starting point for boosting a feasible use of GL materials in a wide spectrum of applications, ranging from electronics to optics, sensors, membranes, functional coatings, and biodevices. Full article

► Show Figures

Figure 1

11 pages, 2618 KiB

Open AccessArticle

Growth of High-Quality Perovskite KTa_1-xNb_xO₃ Thin Films by RF Magnetron Co-Sputtering

by Geon-Hyeong Kang, Ki Chul Jung, Jongbum Kim, JoonHyun Kang, In Soo Kim and Young-Hwan Kim

Coatings 2022, 12(11), 1787; https://doi.org/10.3390/coatings12111787 - 21 Nov 2022

Viewed by 1984

Abstract

In this study, we demonstrate the growth of high-quality KTa_1-xNb_xO₃ (KTN) thin films by using multi-target radio frequency (RF) magnetron co-sputtering with KTaO₃, KNbO₃, and K₂CO₃ targets. KTaO₃ and KNbO [...] Read more.

In this study, we demonstrate the growth of high-quality KTa_1-xNb_xO₃ (KTN) thin films by using multi-target radio frequency (RF) magnetron co-sputtering with KTaO₃, KNbO₃, and K₂CO₃ targets. KTaO₃ and KNbO₃ targets were used to control the Ta/Nb ratio while the K₂CO₃ target was used to supply excess potassium (K) to compensate for the K deficiency. Through careful control of the RF powers applied to each target, high-quality perovskite KTN (x = 0.53) thin films were grown on various single crystal substrates. Variable temperature Raman spectroscopy revealed that the KTN thin films exhibit a ferroelectric phase at room temperature with a Curie temperature of ~403 K. The optical constants n and k of the KTN thin film were also similar to those reported for single KTN crystals. These results present a simple route toward fabricating high-quality perovskite KTN thin films with desired structural and optical properties for various device applications utilizing the RF magnetron co-sputtering method. Full article

(This article belongs to the Section Thin Films)

► Show Figures

Figure 1

12 pages, 3615 KiB

Open AccessArticle

Domesticating a Halotolerant Bacterium of Vibrio sp. LY1024 with Heterotrophic Nitrification–Aerobic Denitrification Property for Efficient Nitrogen Removal in Mariculture Wastewater Treatment

by Lu Wang, Yutong Fu, Shuaijie Wang, Fei Ye, Enming Cui and Qina Sun

Coatings 2022, 12(11), 1786; https://doi.org/10.3390/coatings12111786 - 21 Nov 2022

Cited by 4 | Viewed by 1611

Abstract

Dealing with mariculture wastewater that contains high nitrogenous compounds with efficient biological nitrogen removal technology is challenging but meaningful. The key lies in developing an active microorganism that can spontaneously complete the nitrification–denitrification processes in the marine environment. Herein, a halotolerant heterotrophic nitrification–aerobic [...] Read more.

Dealing with mariculture wastewater that contains high nitrogenous compounds with efficient biological nitrogen removal technology is challenging but meaningful. The key lies in developing an active microorganism that can spontaneously complete the nitrification–denitrification processes in the marine environment. Herein, a halotolerant heterotrophic nitrification–aerobic denitrification (HN-AD) bacterium of Vibrio sp. LY1024 with good nitrogen removal capacity is domesticated to achieve the aforementioned goal. As a result, ammonium (NH₄⁺-N) and nitrate (NO₃⁻-N) removal rates of almost 100% and 98.5% are detected over Vibrio sp. LY1024 at the salinity of 3.5%, even further increasing the salinity of wastewater to 5.5%. Its removal capacity towards both NH₄⁺-N and NO₃⁻-N can still maintain at almost 100% and 94.7%, respectively. Further combining these results with those of intermediate product determination, it can be speculated that the ammonium removal is according to the pathway of NH₄⁺-N → NH₂OH → NO₃⁻-N → N₂O → N₂. Moreover, the influence of wastewater temperature on the nitrogen removal efficiency of Vibrio sp. LY1024 is also considered. The NH₄⁺-N and NO₃⁻-N removal efficiency over Vibrio sp. LY1024 at a relatively low temperature of 15 °C is still up to 97.3% and 76.4%, respectively. Our work provides a promising halotolerant and low-temperature resistance microorganism for the treatment of mariculture wastewater. Full article

(This article belongs to the Special Issue Advanced Technology in Environmental Remediation and Resource Utilization)

► Show Figures

Figure 1

11 pages, 3335 KiB

Open AccessArticle

Towards the Efficient Way of Asphalt Regeneration by Applying Heating and Mechanical Processing

by Vytautas Bucinskas, Andrius Dzedzickis, Mantas Makulavicius, Nikolaj Sesok and Inga Morkvenaite-Vilkonciene

Coatings 2022, 12(11), 1785; https://doi.org/10.3390/coatings12111785 - 21 Nov 2022

Viewed by 1469

Abstract

Asphalt layers renovation includes heating, mechanical processing, and the removal of the layer. Implementation of an alternative method—regenerating the upper asphalt layer, saves the operation time and energy. Common regeneration technologies consume a significant amount of energy and pollute the air during operation. [...] Read more.

Asphalt layers renovation includes heating, mechanical processing, and the removal of the layer. Implementation of an alternative method—regenerating the upper asphalt layer, saves the operation time and energy. Common regeneration technologies consume a significant amount of energy and pollute the air during operation. This research aimed to investigate the improvement of the asphalt layers regeneration process when heating is applied together with mechanical processing. This methodology enables safe energy in the process of asphalt regeneration in terms of heating agent and mechanical processing. The distribution of the asphalt temperature in its cross-section with and without mechanical processing was evaluated experimentally and theoretically using a mathematical model. Experiments were performed in the temperature range from 250 to 450 °C. Mechanical loading was applied by the pressure force of 4500 N. Using mechanical loading together with heating, the best heat transfer into a deeper layer was found when the heating temperature of the asphalt was 250 °C. The asphalt simulation model showed that deeper asphalt layers require more time for the temperature to reach the limit values. Full article

(This article belongs to the Special Issue Application of Cement, Concrete and Asphalt Materials in Pavement)

► Show Figures

Figure 1

12 pages, 4013 KiB

Open AccessArticle

Electrodeposition and Characterization of Poly 3-Amino-1,2,4-Triazole-5-Thiol Films on Brass Electrode in 0.1 M Methanol

by Mohamed Damej, Mohammed Abouchane, Mostafa Doubi, Hamid Erramli, Mohammed Benmessaoud and Najat Hajjaji

Coatings 2022, 12(11), 1784; https://doi.org/10.3390/coatings12111784 - 21 Nov 2022

Cited by 3 | Viewed by 1420

Abstract

The electrochemical synthesis of conductive polymers (CPs) or semiconductors (SCs) is influenced by several parameters, such as the choice of monomers, solvents, support electrolytes, and the nature of dopants, which induce electrical conductivity in conjugated organic polymers. This work describes the electropolymerization of [...] Read more.

The electrochemical synthesis of conductive polymers (CPs) or semiconductors (SCs) is influenced by several parameters, such as the choice of monomers, solvents, support electrolytes, and the nature of dopants, which induce electrical conductivity in conjugated organic polymers. This work describes the electropolymerization of 3-amino-1,2,4-triazole-5-thiol (ATT) on a 60Cu-40Zn brass alloy. The synthesis of polymer film by electrochemical method was carried out by cyclic voltammetry and chronoamperometry in a medium of KOH 0.1 M dissolved in pure methanol CH₃OH. The voltammograms obtained show that the ATT oxidizes anodically at a potential of 1.15 V. The effect of the sweep speed shows that the increase in the sweep speed is accompanied by the increase in the intensity of the first oxidation peak, indicating the acceleration of the process studied, and also indicating that the oxidation reaction of the monomers is essentially irreversible and controlled by a diffusion process. The polymer film analysis by electrochemical impedance spectroscopy shows a capacitive then diffusional behavior—this is a typical effect of conductive polymers. Analysis by EDX justifies the formation of a polymer film on the metal surface. This work was completed by theoretical calculation, which showed that the oxidation of the ATT considerably reduces the energy value of Gap

E_{g a p}

, reaching a value of 2.07 eV—this shows that the polymer film is a semiconductive material. Full article

► Show Figures

Graphical abstract

13 pages, 5818 KiB

Open AccessArticle

Simulation Analysis with Randomly Distributed Multiple Projectiles and Experimental Study of Shot Peening

by Wenxue Qian, Shuanghui Huang, Xiaowei Yin and Liyang Xie

Coatings 2022, 12(11), 1783; https://doi.org/10.3390/coatings12111783 - 21 Nov 2022

Cited by 7 | Viewed by 1638

Abstract

Shot peening technology is used to improve the fatigue strength of materials and parts, and is one of the most effective surface engineering techniques to prolong fatigue life. In this paper, according to the finite element simulation analysis of shot peening, a randomly [...] Read more.

Shot peening technology is used to improve the fatigue strength of materials and parts, and is one of the most effective surface engineering techniques to prolong fatigue life. In this paper, according to the finite element simulation analysis of shot peening, a randomly distributed multiple-shot finite element model was established. The superimposed effects of multiple projectile impact craters in shot peening are fully considered. The effects of shot velocity, shot peening angle and shot coverage on the residual stress field and surface roughness were studied. The alloy steel 20MnTiB, widely used in the automotive industry, was used as the raw material to process the specimens. The shot peening tests of different process parameters were carried out. The test results verified the correctness and accuracy of the random distribution model of multiple-shot. The shot-peening simulation model proposed in this paper allows a more accurate analysis of the effect of shot-peening parameters on the surface residual stress field and helps to quickly set the correct shot-peening process parameters. This paper further investigates the effect of shot peening parameters on fatigue life, providing a basis for the rational development of shot peening solutions. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

► Show Figures

Figure 1

17 pages, 6463 KiB

Open AccessEditor’s ChoiceArticle

Photocatalytic Performance of ZnO/Ag(NPs) Nanocomposite Thin Films under Natural Conditions

by Mouna Khiari, Michaël Lejeune, Mickaël Gilliot, Florica Lazar and Aomar Hadjadj

Coatings 2022, 12(11), 1782; https://doi.org/10.3390/coatings12111782 - 21 Nov 2022

Cited by 2 | Viewed by 2001

Abstract

The original technique developed for the direct incorporation and efficient dispersion of silver metal NPs into ZnO precursor solution allowed us to elaborate nanocomposite thin films with a large effective surface area for interaction with the external environment as well as a large [...] Read more.

The original technique developed for the direct incorporation and efficient dispersion of silver metal NPs into ZnO precursor solution allowed us to elaborate nanocomposite thin films with a large effective surface area for interaction with the external environment as well as a large surface area for metal–semiconductor interaction suitable for surface photocatalysis reactions. Such photocatalysts have the advantage of being in solid form, combining the benefits of the semiconductor material and the metallic nanoparticles embedded in it, while being eco-friendly. Their photocatalytic performance was analyzed under different operating conditions. The improved photocatalytic performance, stability, and reusability of the nanocomposite were demonstrated under both laboratory and natural conditions of use. The results of the present study provide interesting perspectives for the application of these photocatalysts in water treatment. Full article

(This article belongs to the Special Issue Recent Advances in Functional Transparent Semiconductor Films and Coatings)

► Show Figures

Figure 1

13 pages, 5706 KiB

Open AccessArticle

Enhancement of Power Conversion Efficiency with Zinc Oxide as Photoanode and Cyanococcus, Punica granatum L., and Vitis vinifera as Natural Fruit Dyes for Dye-Sensitized Solar Cells

by Ili Salwani Mohamad, Mohd Natashah Norizan, Norsuria Mahmed, Nurnaeimah Jamalullail, Dewi Suriyani Che Halin, Mohd Arif Anuar Mohd Salleh, Andrei Victor Sandu, Madalina Simona Baltatu and Petrica Vizureanu

Coatings 2022, 12(11), 1781; https://doi.org/10.3390/coatings12111781 - 21 Nov 2022

Cited by 6 | Viewed by 1947

Abstract

Ruthenium N719 is a well-known material used as the dye in commercial dye-sensitized solar cell (DSSC) devices. However, it poses risks to human health and the environment over time. On the other hand, titanium dioxide (TiO₂) has low electron mobility and [...] Read more.

Ruthenium N719 is a well-known material used as the dye in commercial dye-sensitized solar cell (DSSC) devices. However, it poses risks to human health and the environment over time. On the other hand, titanium dioxide (TiO₂) has low electron mobility and high recombination losses when used as a photoanode in this photovoltaic technology device. In addition, using Ruthenium as the dye material harms the environment and human health. As an alternative sensitizer to compensate Ruthenium on two different photoanodes (TiO₂ and ZnO), we constructed DSSC devices in this study using three different natural dyes (blueberry, pomegranate, and black grape). In good agreement with the anthocyanin content in the fruits, black grape, with the highest anthocyanin content (450.3 mg/L) compared to other fruit dyes (blueberry—386.6 mg/L and pomegranate—450.3 mg/L), resulted in the highest energy conversion efficiency (3.63%) for the natural dye-based DSSC. Furthermore, this research proved that the electrical performance of natural dye sensitizer in DSSC applications with a ZnO photoanode is better than using hazardous Ru N719 dye with a TiO₂ photoanode owing to the advantage of high electron mobility in ZnO. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Performance Enhancement of Electrode and Biomaterial Coatings)

► Show Figures

Figure 1

13 pages, 14364 KiB

Open AccessArticle

Predicting the Residual Stress of Amorphous Al₂O₃-Y₂O₃ Nano-Laminated Deuterium Permeation Barrier under Thermal Cycles

by Kezhi Huang, Hao Liu, Weijing Wang, Qinghe Yu, Liwu Jiang, Yu Liu, Jing Mi, Lei Hao, Baolong Yuan, Mingkun Liu, Rui Cai and Wei Xiao

Coatings 2022, 12(11), 1780; https://doi.org/10.3390/coatings12111780 - 21 Nov 2022

Viewed by 1541

Abstract

Al₂O₃-Y₂O₃ laminated coating can be applied in fusion reactors to prevent fuel leakage and radiological hazard. However, the residual stress induced by the thermal cycles during the operation of the reactor can cause the failure of [...] Read more.

Al₂O₃-Y₂O₃ laminated coating can be applied in fusion reactors to prevent fuel leakage and radiological hazard. However, the residual stress induced by the thermal cycles during the operation of the reactor can cause the failure of the coating. In order to analyze the problem, finite element models of Al₂O₃-Y₂O₃ laminated coatings with 600 nm of total thickness and different layout were analyzed. The max principal stress site in the coatings is located at the sub-top layer. The max principal stress in laminated coating with the Y₂O₃ sub-top decreases from 657 MPa for a two-layer coating (300 nm) to 598 MPa for a four-layer coating (150 nm). On the contrary, if Al₂O₃ is the sub-top layer, the max principal stress increases from 463 MPa for a two-layer coating (300 nm) to 495 MPa for a four-layer coating (150 nm). The result shows that the more deformable amorphous Al₂O₃ layer in the laminated coating system is more influential to the thermal stress. Full article

(This article belongs to the Special Issue Advances in Thermal Barrier Coatings (TBCs): Materials, Fabrication, Corrosion and Applications)

► Show Figures

Figure 1

5 pages, 175 KiB

Open AccessEditorial

Advances in Surface Functionalization of Lithium Battery Separators and Their In-Service Process Damage Behavior

by Wang Qian, Yang Chen, Ruijie Xu, Caihong Lei and Dahua Chen

Coatings 2022, 12(11), 1779; https://doi.org/10.3390/coatings12111779 - 21 Nov 2022

Viewed by 1438

Abstract

In recent years, with the rapid development of the lithium battery and energy storage industry, lithium-ion/lithium batteries have received extensive attention and have applications in high-power, portable household and power energy storage [...] Full article

(This article belongs to the Special Issue Recent Developments, Applications and Failure Behaviors of Functional Coating Battery Separator)

12 pages, 4275 KiB

Open AccessArticle

The Electronic Structure and Optical Properties of CdGeAs₂ Crystal: A DFT and HSE06 Study

by Suqin Xue, Jing Ning, Bohang Zhang, Qiao Wu, Fuchun Zhang and Weibin Zhang

Coatings 2022, 12(11), 1778; https://doi.org/10.3390/coatings12111778 - 21 Nov 2022

Cited by 1 | Viewed by 2025

Abstract

The electronic structural and optical properties of CdGeAs₂ crystals are calculated by using the Perdew–Burke–Ernzerhof (PBE) functional within generalized gradient approximation (GGA) and the Heyd–Scuseria–Ernzerhof (HSE06) functional. The results show that CdGeAs₂ is an optical crystal with a direct bandgap of [...] Read more.

The electronic structural and optical properties of CdGeAs₂ crystals are calculated by using the Perdew–Burke–Ernzerhof (PBE) functional within generalized gradient approximation (GGA) and the Heyd–Scuseria–Ernzerhof (HSE06) functional. The results show that CdGeAs₂ is an optical crystal with a direct bandgap of 0.71 eV by using the HSE06 functional method, which is closer to the experimental value. The Mulliken population and differential charge density analysis indicate that the Ge–As and Cd–As bonds have covalent properties, and that the covalent bond of Cd–As is visibly stronger than that of the Ge–As bond. The optical properties show that the CdGeAs₂ crystal has strong absorption and reflection in the ultraviolet region and strong transmittance in the infrared region. The average static refractive index of CdGeAs₂ is 2.96, and the static birefractive index is 0.08. The results show that CdGeAs₂ is an excellent optical material of potential applications in the middle and far infrared. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

► Show Figures

Figure 1

33 pages, 2529 KiB

Open AccessReview

Marginal Adaptation and Internal Fit of 3D-Printed Provisional Crowns and Fixed Dental Prosthesis Resins Compared to CAD/CAM-Milled and Conventional Provisional Resins: A Systematic Review and Meta-Analysis

by Mohammed Hussain Dafer Al Wadei, Mohammed E. Sayed, Saurabh Jain, Aparna Aggarwal, Hatem Alqarni, Shilpi Gilra Gupta, Saeed M. Alqahtani, Nasser M. Alahmari, Abdullah Hasan Alshehri, Meena Jain, Abrar A. Ageeli, Saad Saleh AlResayes, Samar Alghamdi, Alhanouf K. Alnajdi and Mafaz M. Gharawi

Coatings 2022, 12(11), 1777; https://doi.org/10.3390/coatings12111777 - 20 Nov 2022

Cited by 12 | Viewed by 4257

Abstract

The aim of this systematic review was to evaluate the marginal fit and internal adaptation of provisional crowns and fixed dental prostheses (FDPs) fabricated using 3D-printing resins and compared them with those fabricated by CAD/CAM (computer-aided designing/computer-aided manufacturing) milling and conventional resins. The [...] Read more.

The aim of this systematic review was to evaluate the marginal fit and internal adaptation of provisional crowns and fixed dental prostheses (FDPs) fabricated using 3D-printing resins and compared them with those fabricated by CAD/CAM (computer-aided designing/computer-aided manufacturing) milling and conventional resins. The null hypotheses tested were that there would be no differences in the marginal fit and internal adaptation of 3D-printed provisional crowns and FDP resins when compared to CAD/CAM-milled and conventional provisional resins. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to construct this systematic review. The focused PICO/PECO (Population, Intervention/Exposure, Comparison, Outcome) question was “Do provisional crowns and FDPs (P) fabricated by 3D-printing (I) have similar marginal adaptation and internal fit (O) when compared to those fabricated by CAD/CAM milling and conventional techniques (C)?”. The protocol used for this systematic review was pre-registered in the International Prospective Register of Systematic Reviews (PROSPERO). Electronic databases (e.g., MEDLINE/PubMed and Web of Science (Core Collection)) were systematically searched for indexed English literature published up to June 2022. In the initial electronic search of the selected databases, 519 articles were identified. Duplicates were removed, and screening was performed to select the articles that met the preset inclusion criteria. Sixteen studies were selected for qualitative analysis, but only ten of them provided comparative data and were selected for quantitative analysis. The modified CONSORT scale was used for qualitative analysis, and most of the included studies were rated to be of moderate quality. Based on the findings, it could be concluded that provisional crowns and FDPs fabricated from 3D-printing resins have a superior marginal fit and internal adaptation when compared to CAD/CAM-milled and conventional provisional resins; thus, they can be used as a dependable alternative to other resins. Full article

(This article belongs to the Special Issue Surface Modifications and Coatings for Implantable Biomaterials)

► Show Figures

Figure 1

13 pages, 5496 KiB

Open AccessArticle

Corrosion Properties of DLC Film in Weak Acid and Alkali Solutions

by Dong Guo, Shuling Zhang, Tenglong Huang, Shuaizheng Wu, Xinghua Ma and Feng Guo

Coatings 2022, 12(11), 1776; https://doi.org/10.3390/coatings12111776 - 20 Nov 2022

Cited by 7 | Viewed by 1816

Abstract

As an important joint material, tantalum (Ta) needs to be studied intensively in terms of wear and corrosion resistance. Two films of Ta/Ti/DLC (diamond-like carbon) (referred to as TD film) and Ta/Ti/TiN/Ti/DLC (referred to as TTTD film) were prepared by magnetron sputtering technology, [...] Read more.

As an important joint material, tantalum (Ta) needs to be studied intensively in terms of wear and corrosion resistance. Two films of Ta/Ti/DLC (diamond-like carbon) (referred to as TD film) and Ta/Ti/TiN/Ti/DLC (referred to as TTTD film) were prepared by magnetron sputtering technology, and their electrochemical corrosion performance in lactic acid and sodium bicarbonate solutions was also investigated. The morphology observation, electrochemical corrosion experiment, and static contact angle measurement were carried out using a scanning electron microscope, electrochemical workstation, and a contact angle meter. This paper mainly discusses and analyzes the corrosion influencing factors and corrosion mechanisms of these two films under two different environments. The 20-day immersion experiments show that the TD film in both solutions results in severe surface corrosion due to its loose structure and many internal defects. In contrast, the surface of the TTTD film with a dense structure, a multilayer structure, and a thicker thickness is not corroded under the same conditions. The electrochemical corrosion experiments show that the corrosion resistance of the TD film is worse than that of the Ta substrate, while the TTTD film has the strongest corrosion resistance, improving the corrosion resistance of the Ta substrate. Although the TD film had a higher sp³ content than the TTTD film, it does not provide protection to the Ta substrate due to increased structural defects in the TD film. The results of the contact angle show that the contact angle of the TTTD film is smaller than that of the TD film in both solutions. However, the TTTD film has the lowest roughness and the densest structure, and thus the TTTD film is more resistant to corrosion. It is finally concluded that the surface morphology and internal structure of the films are the main factors affecting corrosion resistance. This provides an important reference for the application of DLC film in weak alkaline and weak acid environments. Full article

► Show Figures

Figure 1

17 pages, 3556 KiB

Open AccessFeature PaperArticle

How do Graphene Composite Surfaces Affect the Development and Structure of Marine Cyanobacterial Biofilms?

by Maria J. Romeu, Luciana C. Gomes, Francisca Sousa-Cardoso, João Morais, Vítor Vasconcelos, Kathryn A. Whitehead, Manuel F. R. Pereira, Olívia S. G. P. Soares and Filipe J. Mergulhão

Coatings 2022, 12(11), 1775; https://doi.org/10.3390/coatings12111775 - 20 Nov 2022

Cited by 3 | Viewed by 3083

Abstract

The progress of nanotechnology has prompted the development of novel marine antifouling coatings. In this study, the influence of a pristine graphene nanoplatelet (GNP)-modified surface in cyanobacterial biofilm formation was evaluated over a long-term assay using an in vitro platform which mimics the [...] Read more.

The progress of nanotechnology has prompted the development of novel marine antifouling coatings. In this study, the influence of a pristine graphene nanoplatelet (GNP)-modified surface in cyanobacterial biofilm formation was evaluated over a long-term assay using an in vitro platform which mimics the hydrodynamic conditions that prevail in real marine environments. Surface characterization by Optical Profilometry and Scanning Electron Microscopy has shown that the main difference between GNP incorporated into a commercially used epoxy resin (GNP composite) and both control surfaces (glass and epoxy resin) was related to roughness and topography, where the GNP composite had a roughness value about 1000 times higher than control surfaces. The results showed that, after 7 weeks, the GNP composite reduced the biofilm wet weight (by 44%), biofilm thickness (by 54%), biovolume (by 82%), and surface coverage (by 64%) of cyanobacterial biofilms compared to the epoxy resin. Likewise, the GNP-modified surface delayed cyanobacterial biofilm development, modulated biofilm structure to a less porous arrangement over time, and showed a higher antifouling effect at the biofilm maturation stage. Overall, this nanocomposite seems to have the potential to be used as a long-term antifouling material in marine applications. Moreover, this multifactorial study was crucial to understanding the interactions between surface properties and cyanobacterial biofilm development and architecture over time. Full article

(This article belongs to the Special Issue Polymer Thin Films: From Fundamentals to Applications)

► Show Figures

Graphical abstract

9 pages, 2515 KiB

Open AccessFeature PaperArticle

Bi₂O₃-Assisted Sintering of Na₃Zr₂Si₂PO₁₂ Electrolyte for Solid-State Sodium Metal Batteries

by Shangxu Cen, Wentao Mei, Xiangyuan Xing, Yiwei Zeng, Zhiyong Mao, Dajian Wang, Jingjing Chen and Chenlong Dong

Coatings 2022, 12(11), 1774; https://doi.org/10.3390/coatings12111774 - 20 Nov 2022

Cited by 6 | Viewed by 2484

Abstract

Solid-state sodium metal batteries using non-flammable solid-state electrolytes are recognized as next-generation energy storage technology in view of their merits of high safety and low cost. However, the lower ion conductivity (below the application requirements of 10⁻³ S cm⁻¹) and [...] Read more.

Solid-state sodium metal batteries using non-flammable solid-state electrolytes are recognized as next-generation energy storage technology in view of their merits of high safety and low cost. However, the lower ion conductivity (below the application requirements of 10⁻³ S cm⁻¹) and interface issues that exist in electrolytes/electrodes for most solid-state electrolytes hinder their practical application. In this paper, NASICON-type Na₃Zr₂Si₂PO₁₂ (NZSP) electrolytes with enhanced ion conductivity are synthesized by the Bi₂O₃-assisted sintering method. The influence of the Bi₂O₃ sintering agent content on the crystalline phase, microstructure, density and ion conductivity as well as the electrochemical performances applied in batteries for the obtained NZSP electrolytes are investigated in detail. With the presence of Bi₂O₃, the formed Na₃Bi(PO₄)₂ impurity increased the Si/P ratio in the NASICON structure with higher Na⁺ occupancy, then enhanced the ionic conductivity to a level of 1.27 × 10⁻³ S cm⁻¹. Unfortunately, the Bi₂O₃-assisted sintered NZSP shows a degradation in the cycling stability when applied to solid-state sodium batteries because of the decreased interfacial stability with Na anodes. The formation of a Bi-Na alloy during cycling might be conducive to Na dendrite growth in electrolytes, degrading the cycling performance. This work presents a facial method to improve the ion conductivity of NASICON-type electrolytes and gives insight into the interface issues of solid-state sodium metal batteries. Full article

(This article belongs to the Collection Feature Papers of Coatings for Energy Applications)

► Show Figures

Figure 1

3 pages, 163 KiB

Open AccessEditorial

Nanomaterials Applied in Coatings: Synthesis, Structures, Properties, and Applications

by Shoyebmohamad F. Shaikh

Coatings 2022, 12(11), 1773; https://doi.org/10.3390/coatings12111773 - 20 Nov 2022

Cited by 5 | Viewed by 1670

Abstract

Nanomaterials are an innovative class of materials in high demand for a wide range of practical uses [...] Full article

(This article belongs to the Section Functional Polymer Coatings and Films)

16 pages, 10896 KiB

Open AccessEditor’s ChoiceArticle

High Temperature Low Friction Behavior of h-BN Coatings against ZrO₂

by Qunfeng Zeng

Coatings 2022, 12(11), 1772; https://doi.org/10.3390/coatings12111772 - 19 Nov 2022

Cited by 7 | Viewed by 2407

Abstract

This paper presents high temperature low friction behaviors of the h-BN coatings, which were deposited on high-speed tool steel by radio frequency magnetron sputtering. A tribometer was used to investigate high temperature tribological properties of h-BN coatings against ZrO₂ from 500 °C [...] Read more.

This paper presents high temperature low friction behaviors of the h-BN coatings, which were deposited on high-speed tool steel by radio frequency magnetron sputtering. A tribometer was used to investigate high temperature tribological properties of h-BN coatings against ZrO₂ from 500 °C to 800 °C. The surface morphology, mechanical properties and chemical states of the worn surface of the friction pair were characterized and investigated systemically. The experimental results show that h-BN coatings are of significant importance to improve high temperature tribological properties of steel. Moreover, it is found that high temperature super low friction of the friction pairs is successfully achieved due to tribochemistry, which plays a key role in forming the in-situ generated Fe₂O₃/h-BN composites on the worn surface of h-BN coatings. CoFs of the friction pair are as super low as about 0.02 at 800 °C and around 0.03 at 600 °C at the stable stage. The high temperature super low friction mechanism of the friction pair is discussed in detail. The present study opens a new strategy to achieve high temperature super low friction of the friction system during sliding. Full article

(This article belongs to the Special Issue Technologies of Coatings and Surface Hardening for Tool Industry II)

► Show Figures

Figure 1

13 pages, 3867 KiB

Open AccessArticle

Preparation of Pie-Shaped CoMoO₄ with High Capacitive and Photocatalytic Properties by a Solvothermal Method

by Shuoyan Chen, Juan Wu, Gang Wang, Jing Wang, Licai Fan, Jian Hao, Shen Wang, Yang Liu, Hongyu Wu, Yang Li, Jing Gao and Mingli Yang

Coatings 2022, 12(11), 1771; https://doi.org/10.3390/coatings12111771 - 19 Nov 2022

Cited by 3 | Viewed by 1882 | Correction

Abstract

This paper reports a method for fabricating pie-shaped CoMoO₄ nanomaterials. The morphologic characterization and phase analysis showed that the prepared material was CoMoO₄ and presented a pie-shape. Pie-shaped CoMoO₄ electrode materials possess high specific capacitance in three-electrode electrochemical measurement systems. [...] Read more.

This paper reports a method for fabricating pie-shaped CoMoO₄ nanomaterials. The morphologic characterization and phase analysis showed that the prepared material was CoMoO₄ and presented a pie-shape. Pie-shaped CoMoO₄ electrode materials possess high specific capacitance in three-electrode electrochemical measurement systems. When the current density is 1 A/g, the specific capacitance reaches 1902 F/g. In addition, it has good cycle stability. With 10,000 charge–discharge cycle experiments at a current density of 15 A/g, pie-shaped CoMoO₄ has a specific capacity retention ratio of 99.5%. In addition, the CoMoO₄//CNTs device can provide a maximum energy density of 55.6 Wh/kg (1 A/g) and a maximum power density of 10,900 W/kg (15 A/g), showing good electrochemical performance. The photocatalytic properties of pie-shaped CoMoO₄ were also studied. The results show that the degradation rates of MO (methyl orange), MB (methyl blue), and CR (Congo red) can reach 97.8%, 98.8%, and 99.6% at 100 min, 40 min, and 65 min, respectively. The material has good photocatalytic performance. The excellent performance of pie-shaped CoMoO₄ indicates that the electrode material has potential application scenarios in electrode materials and photocatalysis. Full article

(This article belongs to the Special Issue Recent Advances of Nanomaterial: Surface Modification, Characterization, and Application)

► Show Figures

Figure 1

15 pages, 1103 KiB

Open AccessArticle

Assessing Consumers’ Preference and Loyalty towards Biopolymer Films for Food Active Packaging

by Maria-Ioana Socaciu, Veronica Câmpian, Dan-Cristian Dabija, Melinda Fogarasi, Cristina Anamaria Semeniuc, Andersina Simina Podar and Dan Cristian Vodnar

Coatings 2022, 12(11), 1770; https://doi.org/10.3390/coatings12111770 - 19 Nov 2022

Cited by 11 | Viewed by 2740

Abstract

Contemporary society faces numerous food-related challenges: on the one hand, it is becoming increasingly difficult to ensure that people have access to fresh, nutritious, and safe food products around the world, while on the other hand, consumers from ‘low income’ countries are starving, [...] Read more.

Contemporary society faces numerous food-related challenges: on the one hand, it is becoming increasingly difficult to ensure that people have access to fresh, nutritious, and safe food products around the world, while on the other hand, consumers from ‘low income’ countries are starving, while food products are sometimes discarded because it is difficult to prolong shelf-life. To overcome such challenges, edible active films, called biopolymer films, were developed as materials to cover or wrap food products to extend their shelf-life, as they can offer additional protection. Therefore, this article aims to study consumers’ preference and loyalty towards the innovative, active, green, and sustainable characteristics of biopolymer films for the active packaging of food products. A quantitative empirical investigation was carried out among consumers in an emerging market, pinpointing their behavior toward such a novel food packaging material. The conceptual model designed was assessed using structural equation modelling. The results show that consumers tend to accept and prefer biopolymer-film packaging, as it maintains the characteristics of the product and thus extends its shelf-life. The results also revealed consumers’ openness to eco-sustainable consumption and willingness to pay more for the benefits of this packaging. Full article

(This article belongs to the Special Issue Innovations in Active Food Packaging during the Pandemic and into the 'New Normal')

► Show Figures

Figure 1

13 pages, 5413 KiB

Open AccessArticle

Corrosion Behaviors of Fe-22Cr-16Mn-0.55N High-Nitrogen Austenitic Stainless Steel in 3.5% NaCl Solution

by Song Xu, Fengyin Gao, Jianyang Han, Shangfeng Xiong, Xinyu Duan, Fanglin Zha, Bing Yu, Lanlan Yang, Yanxin Qiao, Zhibin Zheng and Jian Chen

Coatings 2022, 12(11), 1769; https://doi.org/10.3390/coatings12111769 - 19 Nov 2022

Cited by 5 | Viewed by 2225

Abstract

In this study, the corrosion behavior of the high-nitrogen austenitic stainless steel (HNS) Fe-22Cr-16Mn-0.55N before and after solution treatment (ST) in 3.5% NaCl solution has been investigated. The effect of a solution temperature of 1100 °C and heat preservation for 30 min on [...] Read more.

In this study, the corrosion behavior of the high-nitrogen austenitic stainless steel (HNS) Fe-22Cr-16Mn-0.55N before and after solution treatment (ST) in 3.5% NaCl solution has been investigated. The effect of a solution temperature of 1100 °C and heat preservation for 30 min on the corrosion resistance and passive film protection of HNS steel was studied. Open-circuit potential, potentiodynamic polarization and electrochemical impedance tests were used to assess the corrosion resistance of treated and untreated steels. In addition, potentiostatic polarization and XPS techniques together with Mott–Schottky curves were applied to determine the composition and properties of the passive films. The results showed that after solution treatment, the grain size of HNS decreased and the grain became more uniform. Although corrosion occurred on HNSs both before and after treatment, solution treatment resulted in greater compactness in passive films, leading to lower carrier density, lower corrosion current density and better corrosion resistance. Full article

(This article belongs to the Topic Properties of the Corroding Interface)

► Show Figures

Figure 1

14 pages, 4160 KiB

Open AccessFeature PaperArticle

Dimensionless Analysis to Determine Elastoplastic Properties of Thin Films by Indentation

by Xu Long, Jiao Li, Ziyi Shen and Yutai Su

Coatings 2022, 12(11), 1768; https://doi.org/10.3390/coatings12111768 - 18 Nov 2022

Cited by 12 | Viewed by 2001

Abstract

By assuming the elastoplastic properties of thin-film materials, a reverse analysis method is proposed by deriving a dimensionless function for the indentation process. The substrate effect is taken into account by assuming a perfect interface between thin-film and substrate materials. In order to [...] Read more.

By assuming the elastoplastic properties of thin-film materials, a reverse analysis method is proposed by deriving a dimensionless function for the indentation process. The substrate effect is taken into account by assuming a perfect interface between thin-film and substrate materials. In order to obtain the applied load–penetration depth (P-h) curves, the indentation process is numerically modeled as an axisymmetric problem with a rigid-body Berkovich indenter on the semi-infinite substrate when performing finite element (FE) simulations. As a typical soft film/hard substrate problem, the elastic substrate is assumed and the power–law model is used to describe the constitutive properties of thin-film materials. Varying elastic modulus (10–50 GPa), yield strength (60–300 MPa), and hardening exponent (0.1–0.5) characterize different elastoplastic mechanical properties of thin-film materials with film thickness of 10–30 μm. Owing to the good trending P-h curves with the maximum indentation depth up to the 2/3 film thickness for different elastoplastic thin-film materials, a dimensionless function is derived and validated based on the predictions by reliable FE simulations. The proposed dimensionless function elegantly elucidates the essential relationship between the elastoplastic mechanical properties of the thin-film material and indentation responses (e.g., loading and unloading variables). The elastoplastic constitutive curves predicted by the proposed reverse method are confirmed to be in good agreement with the stress-strain curves of materials by FE simulations with the randomly selected elastoplastic mechanical properties and film thicknesses. This study provides a theoretical guidance to understand the explicit relationship between elastoplastic mechanical properties of the thin-film material and indentation responses. Full article

(This article belongs to the Special Issue Coatings for Advanced Devices)

► Show Figures

Figure 1

17 pages, 3663 KiB

Open AccessEditor’s ChoiceArticle

Chemical Structure, Optical and Dielectric Properties of PECVD SiCN Films Obtained from Novel Precursor

by Evgeniya Ermakova, Konstantin Mogilnikov, Igor Asanov, Anastasiya Fedorenko, Irina Yushina, Vadim Kichay, Eugene Maksimovskiy and Marina Kosinova

Coatings 2022, 12(11), 1767; https://doi.org/10.3390/coatings12111767 - 18 Nov 2022

Cited by 4 | Viewed by 3204

Abstract

A phenyl derivative of hexamethyldisilazane—bis(trimethylsilyl)phenylamine—was first examined as a single-source precursor for SiCN film preparation by plasma enhanced chemical vapor deposition. The use of mild plasma (20 W) conditions allowed the preparation of highly hydrogenated polymeric-like films. The synthesis was carried out under [...] Read more.

A phenyl derivative of hexamethyldisilazane—bis(trimethylsilyl)phenylamine—was first examined as a single-source precursor for SiCN film preparation by plasma enhanced chemical vapor deposition. The use of mild plasma (20 W) conditions allowed the preparation of highly hydrogenated polymeric-like films. The synthesis was carried out under an inert He atmosphere or under that of NH₃ with the deposition temperature range from 100 to 400 °C. The chemical bonding structure and elemental composition were characterized by Fourier-transform infrared spectroscopy, energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy. The surface morphology was investigated by scanning electron microscopy. Ellipsometric porosimetry, a unique high-precision technique to investigate the porosity of thin films, was applied to examine the porosity of SiCN samples. The films were found to possess a morphologically homogenous dense defect-free structure with a porosity of 2–3 vol.%. SiCN films were studied in terms of their optical and dielectric properties. Depending on the deposition conditions the refractive index ranged from 1.53 to 1.78. The optical bandgap obtained using UV-Vis spectroscopy data varied from 2.7 eV for highly hydrogenated polymeric-like film to 4.7 eV for cross-linked nitrogen-rich film. The dielectric constant was found to decrease from 3.51 to 2.99 with the rise of hydrocarbon groups’ content. The results obtained in this study were compared to the literature data to understand the influence of precursor design to the optical and electrical properties of the films. Full article

(This article belongs to the Special Issue Coatings and Thin Film for Chemical Vapor Deposition (CVD) Application)

► Show Figures

Figure 1

10 pages, 4448 KiB

Open AccessArticle

Improvement of Ferroelectricity in Ce-Doped Hf_0.5Zr_0.5O₂ Thin Films

by Yong-Guang Xiao, Si-Wei Liu, Li-Sha Yang, Yong Jiang, Ke Xiong, Gang Li, Jun Ouyang and Ming-Hua Tang

Coatings 2022, 12(11), 1766; https://doi.org/10.3390/coatings12111766 - 18 Nov 2022

Cited by 6 | Viewed by 2496

Abstract

At present, ion doping is a popular method typically used to regulate the ferroelectric properties of Hf_0.5Zr_0.5O₂ films. In this work, Ce (cerium)–doped Hf_0.5Zr_0.5O₂ (Ce: HZO) films on Pt/TiN/SiO₂/Si substrates were [...] Read more.

At present, ion doping is a popular method typically used to regulate the ferroelectric properties of Hf_0.5Zr_0.5O₂ films. In this work, Ce (cerium)–doped Hf_0.5Zr_0.5O₂ (Ce: HZO) films on Pt/TiN/SiO₂/Si substrates were prepared by the chemical solution deposition (CSD) method. The microstructure and ferroelectric properties of the Ce–doped HZO films were investigated in detail. The experimental results showed that the remanent polarization value of the films with cerium doping concentration of 7 mol% reached 17 μC/cm², which is a significant improvement compared with the undoped Hf_0.5Zr_0.5O₂ films. The reason for this may be the introduction of cerium ions, which can introduce a certain number of oxygen vacancies, thus stabilizing the formation of the orthogonal phase. Interestingly, the films were shown to be nearly fatigue free after 10⁹ cycles of testing. These results demonstrate that cerium ion doping is an effective method for stabilizing the formation of the orthogonal phase of HZO films, and improving the ferroelectricity of HZO thin films. Full article

(This article belongs to the Special Issue Advanced Ferroelectric Materials and Films: Properties and Applications for Post Moorish Era)

► Show Figures

Figure 1

9 pages, 2322 KiB

Open AccessReview

Water-Soluble Holographic Photopolymers for a Sustainable Future—A Review

by Emilia Mitkova Mihaylova

Coatings 2022, 12(11), 1765; https://doi.org/10.3390/coatings12111765 - 18 Nov 2022

Cited by 6 | Viewed by 2399

Abstract

Holographic photopolymers are subject to extensive studies in recent years because they are low-cost, easy-to-handle, self-processing materials, which have a number of advantages over more traditional holographic materials. The development of low-toxicity photopolymers that are environmentally friendly is highly desirable. The availability of [...] Read more.

Holographic photopolymers are subject to extensive studies in recent years because they are low-cost, easy-to-handle, self-processing materials, which have a number of advantages over more traditional holographic materials. The development of low-toxicity photopolymers that are environmentally friendly is highly desirable. The availability of low-toxicity photopolymers will permit the mass production of commercial holograms without harm to the environment. This paper reviews recent developments in low-toxicity water-soluble holographic photopolymers. A novel composition for a water-soluble, low-toxicity photopolymer is described. This new holographic photopolymer has 90% diffraction efficiency in the transmission mode of recording and 50% diffraction efficiency in the reflection mode of recording. This photopolymer has all the necessary holographic characteristics to make it very attractive for commercialisation. The optimised chemical composition of the holographic photopolymer for the production of pressure sensors is addressed. A novel and unique feature of this new material is its high sensitivity to pressure, which can be controlled by changing its composition. Several promising environmentally friendly optical materials are being developed for future holographic applications. The presented review of low-toxicity, water-soluble, holographic photopolymers is the first of its kind. Thus, the importance of the review is twofold—it helps contribute to the development of low-toxicity holographic photopolymers, and it provides insight and new ideas for the development of water-soluble photopolymers for other applications. Full article

(This article belongs to the Special Issue Optoelectronic Thin Film Materials Devices)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Coatings, Volume 12, Issue 11 (November 2022) – 189 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI