Special Issue "Coatings for Harsh Environments"

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

Deadline for manuscript submissions: 30 April 2019

Special Issue Editor

Guest Editor
Dr. Shiladitya Paul

TWI, Cambridge, UK
E-Mail

Special Issue Information

Dear Colleagues,

The operation of numerous safety-critical components in industries around the world rely on protective coatings. These coatings often allow process equipment to be purposeful in environments well beyond the operational limit of the uncoated components. Durability, ease of application, repairability, reliability and long-term performance of such coatings are key to their application. Therefore, this Special Issue of Coatings, “Coatings for Harsh Environments” is devoted to research and review articles on the metallic, non-metallic and composite coatings used in aggressive environments.

In particular, the topics of interest include, but are not limited to:

  • Coatings for High Temperature and Molten Salt Applications
  • Coatings for Mitigating Corrosion in CO2 and H2S Environments
  • Thermal Spray and Cold Spray Coatings for Aggressive Environments
  • Corrosion, Wear and Cavitation Resistant Coatings
  • Coatings for Mitigating Marine Corrosion
  • Coatings for Deep Sea Applications
  • Coatings for Nuclear Applications
  • Coating for Chemical and Petrochemical Plants
  • Coatings for Aeroengine Turbines
  • Coatings for Applications in Space
  • Coatings for Oil Sands and other Oil and Gas Exploration and Production Environments

Dr. Shiladitya Paul
Guest Editor

Manuscript Submission Information

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

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

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (7 papers)

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Research

Open AccessArticle Corrosion Resistance of Boronized, Aluminized, and Chromized Thermal Diffusion-Coated Steels in Simulated High-Temperature Recovery Boiler Conditions
Coatings 2018, 8(8), 257; https://doi.org/10.3390/coatings8080257
Received: 30 May 2018 / Revised: 5 July 2018 / Accepted: 22 July 2018 / Published: 24 July 2018
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Abstract
In this study, the high-temperature molten salt corrosion resistance of bare steels and steels with protective coatings, fabricated by thermal diffusion processes (boronizing, aluminizing and chromizing), were investigated and compared. Surface engineering through thermal diffusion can be used to fabricate protective coatings against
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In this study, the high-temperature molten salt corrosion resistance of bare steels and steels with protective coatings, fabricated by thermal diffusion processes (boronizing, aluminizing and chromizing), were investigated and compared. Surface engineering through thermal diffusion can be used to fabricate protective coatings against corrosion, while alleviating issues around possible cracking and spallation that is typical for conventional thermal-sprayed coatings. In this regard, samples of low carbon steel and 316 stainless steel substrates were boronized, chromized, and aluminized through a proprietary thermal diffusion process, while some of the samples were further coated with additional thin oxide and non-oxide layers to create new surface architectures. In order to simulate the actual corrosion conditions in recovery boilers (e.g., from black liquor combustion), the surfaces of the samples sprayed with a modeling salt solution, were exposed to low-temperature (220 C) and high-temperature (600 C) environments. According to microstructural and X-ray diffraction (XRD) studies and results of hardness determination, the coatings with multilayered architectures, with and without additional oxide layers, showed successful resistance to corrosive attack over bare steels. In particular, the samples with boronized and chromized coatings successfully withstood low-temperature corrosive attack, and the samples with aluminized coatings successfully resisted both low- and high-temperature molten salt corrosive attacks. The results of this study conducted for the first time for the thermal diffusion coatings suggest that these coatings with the obtained architectures may be suitable for surface engineering of large-sized steel components and tubing required for recovery boilers and other production units for pulp and paper processing and power generation. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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Open AccessArticle Oxidation Behavior of MoSi2-Coated TZM Alloys during Isothermal Exposure at High Temperatures
Coatings 2018, 8(6), 218; https://doi.org/10.3390/coatings8060218
Received: 15 May 2018 / Revised: 7 June 2018 / Accepted: 8 June 2018 / Published: 11 June 2018
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Abstract
Coating properties and oxidation behaviors of Si pack cementation-coated TZM (Mo-0.5Ti-0.1Zr-0.02C) alloys were investigated in order to understand the stability of the coating layer at high temperatures up to 1350 °C in an ambient atmosphere. After the pack cementation coatings, MoSi2 and
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Coating properties and oxidation behaviors of Si pack cementation-coated TZM (Mo-0.5Ti-0.1Zr-0.02C) alloys were investigated in order to understand the stability of the coating layer at high temperatures up to 1350 °C in an ambient atmosphere. After the pack cementation coatings, MoSi2 and Mo5Si3 layers were formed. When MoSi2-coated TZM alloys were oxidized in air at high temperatures, the Si in the outer MoSi2 layer diffused and formed SiO2. Also, due to the diffusion of Si, the MoSi2 layer was transformed into a columnar shaped Mo5Si3 phase. During isothermal oxidation, the Mo5Si3 phase was formed both within the coated MoSi2 layer and between the MoSi2 and the substrate. The coating properties and the oxidation behavior of the Si pack-coated TZM alloys were discussed along with the identification of growth kinetics. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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Open AccessArticle Influence of Lamellar Interface Morphology on Cracking Resistance of Plasma-Sprayed YSZ Coatings
Coatings 2018, 8(5), 187; https://doi.org/10.3390/coatings8050187
Received: 21 March 2018 / Revised: 4 May 2018 / Accepted: 11 May 2018 / Published: 15 May 2018
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Abstract
Splat morphology is an important factor that influences the mechanical properties and durability of thermal barrier coatings (TBCs). In this study, yttria-stabilized zirconia (YSZ) coatings with different lamellar interface morphologies were deposited by atmospheric plasma spraying (APS) using feedstocks with different particle sizes.
[...] Read more.
Splat morphology is an important factor that influences the mechanical properties and durability of thermal barrier coatings (TBCs). In this study, yttria-stabilized zirconia (YSZ) coatings with different lamellar interface morphologies were deposited by atmospheric plasma spraying (APS) using feedstocks with different particle sizes. The influence of lamellar interface roughness on the cracking resistance of the coatings was investigated. Furthermore, the thermal shock and erosion resistance of coatings deposited by two different powders was evaluated. It was found that the particle size of the feedstock powder affects the stacking morphology of the splat that forms the coating. Coatings fabricated from coarse YSZ powders (45–60 μm) show a relatively rough inter-lamellar surface, with a roughness about 3 times greater than those faricated from fine powders (15–25 μm). Coatings prepared with fine powders tend to form large cracks parallel to the substrate direction under indentation, while no cracking phenomena were found in coatings prepared with coarse powders. Due to the higher cracking resistance, coatings prepared with coarse powders show better thermal shock and erosion resistances than those with fine powders. The results of this study provide a reference for the design and optimization of the microstructure of TBCs. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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Open AccessArticle Corrosion Resistance of Pipeline Steel with Damaged Enamel Coating and Cathodic Protection
Coatings 2018, 8(5), 185; https://doi.org/10.3390/coatings8050185
Received: 20 February 2018 / Revised: 12 April 2018 / Accepted: 9 May 2018 / Published: 14 May 2018
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Abstract
This paper presents the first report on the corrosion resistance of pipeline steel with damaged enamel coating and cathodic protection in 3.5 wt % NaCl solution. In particular, dual cells are set up to separate the solution in contact with the damaged and
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This paper presents the first report on the corrosion resistance of pipeline steel with damaged enamel coating and cathodic protection in 3.5 wt % NaCl solution. In particular, dual cells are set up to separate the solution in contact with the damaged and intact enamel coating areas, to produce a local corrosion resistance measurement for the first time. Enamel-coated steel samples, with two levels of cathodic protection, are tested to investigate their impedance by electrochemical impedance spectroscopy (EIS) and their cathodic current demand by a potentiostatic test. Due to its glass transition temperature, the enamel-coated pipeline can be operated on at temperatures up to 400 °C. The electrochemical tests show that cathodic protection (CP) can decelerate the degradation process of intact coating and delay the electrochemical reactions at the enamel-steel interface. However, CP has little effect on the performance of coating once damaged and can prevent the exposed steel from corrosion around the damaged site, as verified by visual inspections. Scanning electron microscopy (SEM) indicated no delamination at the damaged enamel–steel interface due to their chemical bond. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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Open AccessArticle Enhancement of the Corrosion Resistance of 304 Stainless Steel by Cr–N and Cr(N,O) Coatings
Coatings 2018, 8(4), 132; https://doi.org/10.3390/coatings8040132
Received: 27 February 2018 / Revised: 29 March 2018 / Accepted: 2 April 2018 / Published: 5 April 2018
Cited by 1 | PDF Full-text (25338 KB) | HTML Full-text | XML Full-text
Abstract
Chromium nitride and oxynitride coatings were deposited as monolayers ((Cr–N), Cr(N,O)) and bilayers (Cr–N/Cr(N,O), Cr(N,O)/Cr–N) on 304 steel substrates by reactive cathodic arc method. The coatings were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), surface profilometry,
[...] Read more.
Chromium nitride and oxynitride coatings were deposited as monolayers ((Cr–N), Cr(N,O)) and bilayers (Cr–N/Cr(N,O), Cr(N,O)/Cr–N) on 304 steel substrates by reactive cathodic arc method. The coatings were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), surface profilometry, and scratch tester. The anticorrosive properties of the coatings were assessed by electrochemical tests in 0.10 M NaCl + 1.96 M H2O2, carried out at 24 °C. Cr2N, CrN, and Cr(N,O) phases were identified in the coatings by grazing incidence X-ray diffraction (GI-XRD) measurements. The measured adhesion values ranged from 19 N to 35 N, the highest value being obtained for the bilayer with Cr(N,O) on top. Electrochemical tests showed that Cr(N,O) presence in both mono- and bilayered coatings determined the lowest damage in corrosive solution, as compared to the Cr–N coatings. This improvement was ascribed to the more compact structure, lower coatings porosity, and smoother surface. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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Open AccessArticle Wear Transition of CrN Coated M50 Steel under High Temperature and Heavy Load
Coatings 2017, 7(11), 202; https://doi.org/10.3390/coatings7110202
Received: 22 September 2017 / Revised: 3 November 2017 / Accepted: 15 November 2017 / Published: 20 November 2017
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Abstract
The combination of high temperature indentation and wear test provides a useful way to investigate wear of CrN coating and wear transition mechanisms. In this paper, the high temperature hardness of CrN coatings and load bearing capacity, Lb, of CrN coated
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The combination of high temperature indentation and wear test provides a useful way to investigate wear of CrN coating and wear transition mechanisms. In this paper, the high temperature hardness of CrN coatings and load bearing capacity, Lb, of CrN coated M50 disks were determined from spherical indentation at temperatures up to 500 °C. Wear tests with different normal loads were carried out at the same temperatures as the indentation tests. The results show that wear mechanism of CrN coating changes with external load, P, and temperature, T. Under a tested condition of P < Lb and T < 315 °C, abrasive is the dominant wear mechanism for CrN coating. Under a tested condition of P < Lb and T ≥ 315 °C, wear of CrN coating transitions into mild oxidation wear due to the lubricating effect of chromium oxide film. Under a tested condition of P > Lb and T < 315 °C, wear of CrN coating was controlled by coating fracture. Under a tested condition of P > Lb and T ≥ 315 °C, wear of CrN coating transitions into the severe wear mode, due to the tensile fracture of oxidation films, thereby leading to adhesion between CrN coating and tribo-counterpart. The presented method can be helpful in predicting permissible load and working temperature in tribological applications of CrN coating. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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Open AccessArticle Effect of Initial Surface Roughness on Cavitation Erosion Resistance of Arc-Sprayed Fe-Based Amorphous/Nanocrystalline Coatings
Coatings 2017, 7(11), 200; https://doi.org/10.3390/coatings7110200
Received: 23 September 2017 / Revised: 18 October 2017 / Accepted: 1 November 2017 / Published: 14 November 2017
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Abstract
The arc spraying process was used to prepare Fe-based amorphous/nanocrystalline coating. The cavitation erosion behaviors of FeNiCrBSiNbW coatings with different surface roughness levels were investigated in distilled water. The results showed that FeNiCrBSiNbW coating adhered well to the substrate, and was compact with
[...] Read more.
The arc spraying process was used to prepare Fe-based amorphous/nanocrystalline coating. The cavitation erosion behaviors of FeNiCrBSiNbW coatings with different surface roughness levels were investigated in distilled water. The results showed that FeNiCrBSiNbW coating adhered well to the substrate, and was compact with porosity of less than 2%. With increasing initial surface roughness, the coatings showed an increase in mass loss of cavitation erosion damage. The amount of pre-existing defects on the initial surface of the coatings was found to be a significant factor for the difference in the cavitation erosion behavior. The cavitation erosion damage for the coatings was a brittle erosion mode. The evolution of the cavitation erosion mechanism of the coatings with the increase of the initial surface roughness was micro-cracks, pits, detachment of fragments, craters, cracks, pullout of the un-melted particle, and massive exfoliations. Full article
(This article belongs to the Special Issue Coatings for Harsh Environments)
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