Special Issue "Development and Characterization of Nanostructured Functional Coatings/Films"

A special issue of Coatings (ISSN 2079-6412).

Deadline for manuscript submissions: closed (31 July 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Wei Gao

Department of Chemical and Materials Engineering, The University of Auckland, Auckland, New Zealand
Website | E-Mail
Guest Editor
Prof. Dr. Yuxin Wang

School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu, China
Website | E-Mail

Special Issue Information

Dear Colleagues,

Nanostructured coatings/films have been widely studied due to their various excellent and controllable prperties. Recently, numerous study emerged on the development of nanostructured functional coatings and films by different fabrication methods, including electrochemical deposition, magnetron sputtering, CVD, PVD, and sol-gel methods.

This Special Issue will present the recent research progress of the nanostructured functional coatings/films, including novel fabrication process, special microstructure control, and resulted unique properties. It will address the latest development in coatings design, synthesis, characterisation, and applications.

This Special Issue will consist of original research and review articles. It will offer the readers the newest R&D work on nanostructured functional coatings and related techniques. In particular, the topics of interest include, but are not limited to:

  • New design and novel fabrication methods of nanostructured functional coatings;
  • Systematical microstructure characterization of nanostructured functional coatings;
  • Improved properties of nanostructured functional coatings;
  • Case studies on the performance of nanostructured functional coatings.

Prof. Dr. Wei Gao
Prof. Dr. Yuxin Wang
Guest Editors

Published Papers (8 papers)

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Research

Open AccessArticle Cavitation Erosion and Jet Impingement Erosion Behavior of the NiTi Coating Produced by Air Plasma Spraying
Coatings 2018, 8(10), 346; https://doi.org/10.3390/coatings8100346
Received: 17 July 2018 / Revised: 24 August 2018 / Accepted: 9 September 2018 / Published: 28 September 2018
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Abstract
Cavitation erosion and jet impingement erosion can result in a great loss of materials. NiTi alloy is a very promising candidate to acquire cavitation erosion resistance and jet impingement erosion resistance because of its superelasticity. Due to the high cost and poor workability
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Cavitation erosion and jet impingement erosion can result in a great loss of materials. NiTi alloy is a very promising candidate to acquire cavitation erosion resistance and jet impingement erosion resistance because of its superelasticity. Due to the high cost and poor workability of NiTi alloy, many people tried to overcome such drawbacks by preparing NiTi coatings on the basis of deteriorating the good properties as little as possible. From the aspect of the application of NiTi coating, the erosion resistance should be evaluated comprehensively. One of these evaluations involves the comparison of cavitation erosion resistance and jet impingement erosion resistance of NiTi. This evaluation has not been made thus far. Thus, in this study, the NiTi coating was prepared by air plasma spraying (APS) using pre-alloyed NiTi powder. Its microstructure, chemical composition and phase transformation were identified. Cavitation erosion behavior and jet impingement erosion behavior of the as-sprayed NiTi coating were compared. The results showed that the coating exhibited better jet impingement erosion resistance than cavitation erosion resistance. This was attributed to the oxides, impurities, cracks and pores that existed in the coating, whose effects on deteriorating the cavitation erosion were far greater than those worsening the jet impingement erosion. Full article
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Open AccessArticle A Novel Electrolytic Plasma Spraying Preparation SiO2/SiC Coating on Carbon Fiber Fabric
Coatings 2018, 8(10), 344; https://doi.org/10.3390/coatings8100344
Received: 24 July 2018 / Revised: 1 September 2018 / Accepted: 21 September 2018 / Published: 27 September 2018
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Abstract
A good quality of SiO2/SiC coating was successfully fabricated on carbon fiber fabric by a novel electrolytic plasma spraying method, where Na2SiO3·9H2O aqueous solution was used as an electrolyte. In this study, we discussed the
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A good quality of SiO2/SiC coating was successfully fabricated on carbon fiber fabric by a novel electrolytic plasma spraying method, where Na2SiO3·9H2O aqueous solution was used as an electrolyte. In this study, we discussed the effect of spraying distance on the coating. The microstructure and composition coating were characterized by scanning electron microscopy with energy-dispersive spectroscopy and XPS, respectively. An effective coating can be easily prepared within several tens of seconds through this approach by adjusting the spraying distance. Results show that the sample oxidation resistance temperature was up to 1000 °C while the spraying distance was 15 mm, and tensile strength increased by 73 MPa after heat treatment at 900 °C for 20 min. The study provides additional insights into the feasibility of modification of carbon fiber fabric. Meanwhile, this method can be expected to extend to the fabrication of other oxide coatings or the modification of the surfaces of other complicated and/or large-scale easily oxidized materials. Full article
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Open AccessArticle Finite Element Simulation of Temperature and Stress Field for Laser Cladded Nickel-Based Amorphous Composite Coatings
Coatings 2018, 8(10), 336; https://doi.org/10.3390/coatings8100336
Received: 24 July 2018 / Revised: 18 September 2018 / Accepted: 19 September 2018 / Published: 24 September 2018
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Abstract
In this paper, a nickel-based amorphous composite coating was obtained on the carbon steel surface by the laser cladding process. The thermal field and stress distribution were simulated by using ANSYS finite element software where the moving heat source and powder feeding were
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In this paper, a nickel-based amorphous composite coating was obtained on the carbon steel surface by the laser cladding process. The thermal field and stress distribution were simulated by using ANSYS finite element software where the moving heat source and powder feeding were modelled by the “Element birth and death” method. The simulation results were verified by comparing the cross-sectional profile of fusion lines and X-ray stress measurements, respectively. The results on thermal field showed that the cooling rate of the coating could reach up to 10389.15 K/s and it gradually decreased from the outside surface to the interior, which promoted the formation of amorphous phase. The simulated stress field showed that the coating was in the state of tensile stress after cladding and the longitudinal stress was larger than the transverse stress. The coating was experienced with tensile plastic deformation along the laser scanning direction, which resulted in longitudinal residual stress. A higher stress concentration was occurred between the coating layer and substrate, which increased the susceptibility of crack formation. The test results on transverse residual stress were generally consistent with the simulation. On the contrary, the measured longitudinal stress was nearly close to zero, which was not in agreement with the model due to the formation of cracks. Full article
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Open AccessArticle Bioceramic Layers with Antifungal Properties
Coatings 2018, 8(8), 276; https://doi.org/10.3390/coatings8080276
Received: 11 July 2018 / Revised: 30 July 2018 / Accepted: 3 August 2018 / Published: 8 August 2018
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Abstract
The sol-gel method was used to synthesize the silver doped hydroxyapatite (Ag:HAp) gels in order to produce the antifungal composite layers. The pure Ti disks were used as the substrate for the composite layers. Important information about suspensions used to make Ag:HAp composite
[...] Read more.
The sol-gel method was used to synthesize the silver doped hydroxyapatite (Ag:HAp) gels in order to produce the antifungal composite layers. The pure Ti disks were used as the substrate for the composite layers. Important information about suspensions used to make Ag:HAp composite layers were obtained from an ultrasonic technique. The identification of the phase composition of the Ag:HAp composite layers was accomplished X-ray diffraction (XRD). The morphology and the thickness of the layers was evaluated using scanning electron microscopy (SEM). The uniform distribution of the constituent elements (Ag, Ca, P, and O) in both analyzed samples was observed. The antifungal activity of the samples against Candida albicans ATCC 10231 microbial strain were investigated immediately after their preparation and six months later. SEM and confocal laser scanning microscopy (CLSM) images showed that the composite layers at the two time intervals exhibited a strong antifungal activity against Candida albicans ATCC 10231 and completely inhibited the biofilm formation. Full article
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Open AccessArticle Adhesion Performance of Electrodeposited Ni Films with Different Treating Methods
Coatings 2018, 8(6), 201; https://doi.org/10.3390/coatings8060201
Received: 17 April 2018 / Revised: 14 May 2018 / Accepted: 17 May 2018 / Published: 25 May 2018
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Abstract
The adhesion strength between thin films has a significant effect on performance of micro-devices. It is introduced that the effects of three pre-treatment methods: acid, pulse reverse current and anodic current, on the adhesion performance of electrodeposited Ni films on Ni substrate. The
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The adhesion strength between thin films has a significant effect on performance of micro-devices. It is introduced that the effects of three pre-treatment methods: acid, pulse reverse current and anodic current, on the adhesion performance of electrodeposited Ni films on Ni substrate. The adhesion strength, surface and fracture morphology of the Ni films were investigated. The dense oxide films on the Ni substrate were removed effectively by using the anodic dissolution current method in the acidic chloride solutions. Meanwhile, the Ni films treated with specific treatment conditions produced different roughness, which was responsible for the improved adhesion strength. The adhesion strength of the Ni films increased up to 629.8 MPa when substrates were treated with anodic current density of 30 mA/cm2 for 10 min, which is nearly two times higher than that of films treated by 5 vol % HCl for 10 min. The results indicate that the anodic current treatment method effectively improves the adhesion strength of Ni films. Full article
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Open AccessFeature PaperArticle X-ray Microanalysis of Precious Metal Thin Films: Thickness and Composition Determination
Received: 4 December 2017 / Revised: 9 February 2018 / Accepted: 12 February 2018 / Published: 24 February 2018
Cited by 2 | PDF Full-text (2080 KB) | HTML Full-text | XML Full-text
Abstract
Measuring the thickness and the composition of precious metal thin films is a challenging task. Currently, the available techniques for thickness measurements are either destructive or need heavy assumptions on the nature of the sample, relying on information that are not always available
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Measuring the thickness and the composition of precious metal thin films is a challenging task. Currently, the available techniques for thickness measurements are either destructive or need heavy assumptions on the nature of the sample, relying on information that are not always available with sufficient accuracy. In this paper we propose a new methodology based on X-ray microanalysis that can complement, with better lateral resolution, the use of X-ray Fluorescence, the most widely employed technique for measuring the thickness of electrodeposited coatings. The proposed method employs a combination of energy dispersive microanalysis spectra acquisition and Monte Carlo simulation. The effectiveness of the technique has been demonstrated by the measure of the thickness and the composition of a thin 24 kt gold electroplated film that contained small amount of nickel. Results have been validated by comparing data with those obtained by X-ray fluorescence and the scanning electron microscopy of metallographic cross-sections. Full article
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Open AccessArticle Tuning the Friction of Silicon Surfaces Using Nanopatterns at the Nanoscale
Received: 23 November 2017 / Accepted: 23 November 2017 / Published: 22 December 2017
Cited by 1 | PDF Full-text (5441 KB) | HTML Full-text | XML Full-text
Abstract
Friction and wear become significant at small scale lengths, particularly in MEMS/NEMS. Nanopatterns are regarded as a potential approach to solve these problems. In this paper, we investigated the friction behavior of nanopatterned silicon surfaces with a periodical rectangular groove array in dry
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Friction and wear become significant at small scale lengths, particularly in MEMS/NEMS. Nanopatterns are regarded as a potential approach to solve these problems. In this paper, we investigated the friction behavior of nanopatterned silicon surfaces with a periodical rectangular groove array in dry and wear-less single-asperity contact at the nanoscale using molecular dynamics simulations. The synchronous and periodic oscillations of the normal load and friction force with the sliding distance were determined at frequencies defined by the nanopattern period. The linear load dependence of the friction force is always observed for the nanopatterned surface and is independent of the nanopattern geometry. We show that the linear friction law is a formal Amontons’ friction law, while the significant linear dependence of the friction force-versus-real contact area and real contact area-versus-normal load captures the general features of the nanoscale friction for the nanopatterned surface. Interestingly, the nanopattern increases the friction force at the nanoscale, and the desired friction reduction is also observed. The enlargement and reduction of the friction critically depended on the nanopattern period rather than the area ratio. Our simulation results reveal that the nanopattern can modulate the friction behavior at the nanoscale from the friction signal to the friction law and to the value of the friction force. Thus, elaborate nanopatterning is an effective strategy for tuning the friction behavior at the nanoscale. Full article
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Open AccessArticle Multi-Walled Carbon Nanotube-Assisted Electrodeposition of Silver Dendrite Coating as a Catalytic Film
Coatings 2017, 7(12), 232; https://doi.org/10.3390/coatings7120232
Received: 17 November 2017 / Revised: 7 December 2017 / Accepted: 12 December 2017 / Published: 14 December 2017
Cited by 8 | PDF Full-text (2294 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A multi-walled carbon nanotube (MWCNT)-coated indium tin oxide (ITO) slide was used as a platform for the growth of a silver dendrite (Ag-D) film using cyclic voltammetry. The particular dendritic nanostructures were formed by the diffusion-limited-aggregation model due to the potential difference between
[...] Read more.
A multi-walled carbon nanotube (MWCNT)-coated indium tin oxide (ITO) slide was used as a platform for the growth of a silver dendrite (Ag-D) film using cyclic voltammetry. The particular dendritic nanostructures were formed by the diffusion-limited-aggregation model due to the potential difference between the MWCNTs and the ITO surface. The Ag-D-coated ITO film was then used for the catalytic degradation of methyl orange (MO) and methylene blue (MB) under static aqueous conditions. The network structure of the Ag-D allows the efficient diffusion of MO and MB, and consequently enhances the catalytic performance. Since the thin film is much easier to use for the post-treatment of powder catalysts, the proposed method shows great potential in many catalytic applications. Full article
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