Research

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21 pages, 6695 KiB

Open AccessArticle

A Comparative Study of the Corrosion Behavior of P110 Casing Steel in Simulated Concrete Liquid Containing Chloride and Annulus Fluid from an Oil Well

by Yang Li, Zhongxu Cai, Lijuan Huang and Ruiquan Liao

Coatings 2024, 14(3), 294; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings14030294 - 28 Feb 2024

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Abstract

The corrosion behavior of P110 casing steel in simulated concrete liquid and simulated annulus fluid was investigated to reveal the corrosion pattern and protective properties of corrosion products in the two environments. Potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), Mott–Schottky tests, and electrochemical [...] Read more.

The corrosion behavior of P110 casing steel in simulated concrete liquid and simulated annulus fluid was investigated to reveal the corrosion pattern and protective properties of corrosion products in the two environments. Potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), Mott–Schottky tests, and electrochemical noise (EN) tests were used to study the corrosion behavior of P110 casing steel in simulated concrete liquid and simulated annulus fluid saturated with CO₂. Scanning electron microscopy (SEM) combined with Energy-Dispersive Spectrometer (EDS) mapping was used to characterize the corrosion morphology and elemental distribution of P110 casing steel. The results show that the corrosion resistance of P110 casing steel deteriorates with the increasing immersion days in the simulated annulus fluid, the impedance decreases gradually, and the corrosion-product film shows a loose and porous structure. In the simulated concrete liquid, under the condition of containing a low concentration of Cl⁻, the protection of the corrosion products gradually increases with the extension of immersion days. With the increasing concentration of Cl⁻ and the extension of immersion days, the electrochemical noise resistance and charge transfer resistance of P110 steel decrease gradually, and the protective property of the corrosion-product film decreases, which is capable of forming steady pitting corrosion. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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13 pages, 6105 KiB

Open AccessArticle

Improving Optical and Electrical Characteristics of GaN Films via 3D Island to 2D Growth Mode Transition Using Molecular Beam Epitaxy

by Thi Thu Mai, Jin-Ji Dai, Wu-Ching Chou, Hua-Chiang Wen, Le Trung Hieu and Huy Hoang Luc

Coatings 2024, 14(2), 191; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings14020191 - 01 Feb 2024

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Abstract

Molecular beam epitaxy (MBE) is demonstrated as an excellent growth technique for growing a low-defect GaN channel layer, which is crucial for controlling vertical leakage current and improving breakdown voltage (BV) in GaN-based high-electron mobility transistors (HEMTs). The 3D islands to 2D growth [...] Read more.

Molecular beam epitaxy (MBE) is demonstrated as an excellent growth technique for growing a low-defect GaN channel layer, which is crucial for controlling vertical leakage current and improving breakdown voltage (BV) in GaN-based high-electron mobility transistors (HEMTs). The 3D islands to 2D growth mode transition approach was induced by modulating substrate growth temperature (Tsub), displaying an overall improvement in film quality. A comprehensive investigation was conducted into the effects of Tsub on surface morphologies, crystal quality, and the optical and electrical properties of GaN films. Optimal results were achieved with a strain-relaxed GaN film grown at 690 °C, exhibiting significantly improved surface characteristics (root-mean-square roughness, Rq = 0.3 nm) and impressively reduced edge dislocations. However, the film with the smoothest surface roughness, attributed to the effect of the Ga-rich condition, possessed a high surface pit density, negatively affecting optical and electrical properties. A reduction in defect-related yellow emission further confirmed the enhanced crystalline quality of MBE GaN films. The optimized GaN film demonstrated outstanding electrical properties with a BV of ~1450 V, surpassing that of MOCVD GaN (~1180 V). This research significantly contributes to the advancement of MBE GaN-based high electron mobility transistor (HEMT) applications by ensuring outstanding reliability. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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17 pages, 8300 KiB

Open AccessArticle

Epitaxial Growth of Cobalt Oxide Thin Films on Sapphire Substrates Using Atmospheric Pressure Mist Chemical Vapor Deposition

by Hou-Guang Chen, Huei-Sen Wang, Sheng-Rui Jian, Tung-Lun Yeh and Jing-Yi Feng

Coatings 2023, 13(11), 1878; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings13111878 - 01 Nov 2023

Cited by 1 | Viewed by 1244

Abstract

This study demonstrated the epitaxial growth of single-phase (111) CoO and (111) Co₃O₄ thin films on a-plane sapphire substrates using an atmospheric pressure mist chemical vapor deposition (mist-CVD) process. The phase structure of the grown cobalt oxide films was [...] Read more.

This study demonstrated the epitaxial growth of single-phase (111) CoO and (111) Co₃O₄ thin films on a-plane sapphire substrates using an atmospheric pressure mist chemical vapor deposition (mist-CVD) process. The phase structure of the grown cobalt oxide films was manipulated by controlling the growth temperature and process ambient, confirmed through X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Furthermore, the electrical properties of Co₃O₄ films were significantly improved after thermal annealing in oxygen ambient, exhibiting a stable p-type conductivity with an electrical resistivity of 8.35 Ohm cm and a carrier concentration of 4.19 × 10¹⁶ cm⁻³. While annealing CoO in oxygen atmosphere, the Co₃O₄ films were found to be most readily formed on the CoO surface due to the oxidation reaction. The orientation of the atomic arrangement of formed Co₃O₄ was epitaxially constrained by the underlying CoO epitaxial layer. The oxidation of CoO to Co₃O₄ was largely driven by outward diffusion of cobalt cations, resulting in the formation of pores in the interior of formed Co₃O₄ films. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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11 pages, 6583 KiB

Open AccessArticle

Collision Cascade in a Silicon-Based Device under Energetic Ar Ions Irradiation

by Guoying Liang, Baoming Xu and Xiaoyun Wei

Coatings 2023, 13(11), 1828; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings13111828 - 25 Oct 2023

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Abstract

Silicon, as the basic material of biochips and electronic devices, is often exposed to irradiation environments, and its radiation resistance has attracted much attention in recent decades. We calculated collision cascade in a silicon-based device under energetic Ar ions irradiation by using Monte [...] Read more.

Silicon, as the basic material of biochips and electronic devices, is often exposed to irradiation environments, and its radiation resistance has attracted much attention in recent decades. We calculated collision cascade in a silicon-based device under energetic Ar ions irradiation by using Monte Carlo and molecular dynamics simulations. The difference in vacancy probability density under different energetic incident ion irradiation is caused by the penetrating power and the straggling power of incident ions. The kinetic energy of an incident ion determines the size of local collision cascade density; a high energy incident ion can induce greater local collision cascade density. The efficiency of transferring energy from incident ions to target electrons at the silicon surface is more than in silicon, and the recoil atoms dissipate most of their energy at the lattice sites where they are stopping. These results provide more insight into the radiation resistance of silicon-based devices. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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20 pages, 3585 KiB

Open AccessArticle

Principle and Method for Determining the Calendar Safety Life of Aircraft Structural Protection Systems

by Teng Zhang, Tianyu Zhang, Yuting He, Bo Hou and Changfan Li

Coatings 2023, 13(6), 976; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings13060976 - 24 May 2023

Viewed by 1077

Abstract

The calendar safety life of the surface protection system in aircraft structures is the time limit for it to be used without functional failure at a certain level of reliability and confidence. The reliability of such protection systems and the operational safety and [...] Read more.

The calendar safety life of the surface protection system in aircraft structures is the time limit for it to be used without functional failure at a certain level of reliability and confidence. The reliability of such protection systems and the operational safety and economy of the structure are closely related. This paper firstly establishes two methods for determining the calendar safety life of aircraft structural protection systems under a single service environment and in multiple service environments. A method for determining the reliability of the calendar safety life of the aircraft structural protection system was proposed, and an expression of the relationship between the maintenance costs for the aircraft fleet and the reliability of the calendar safety life of the aircraft structural protection system based on the relationship between the amount of corrosion damage to the structural substrate and the corrosion time and the expression of the calendar safety life of the protection system was established. Finally, taking a hypothetical aircraft fuselage wall plate connection structure as an example, an alternating corrosion fatigue test with protection system specimens was carried out. The process for determining the calendar safety life of the structural protection system and its reliability are given. This method is important to ensure the safety of aircraft structures, improve the efficiency of use, and reduce maintenance costs. Generally speaking, the reliability of the calendar safety life of the structure is 99.9%, and after the analysis in this paper, the reliability of the structural protection system is about 70%. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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19 pages, 6590 KiB

Open AccessArticle

Experimental Study on Bond Behavior between Steel Rebar and PVA Fiber-Reinforced Concrete

by Xuhui Zhang, Qi Lu and Yang Wang

Coatings 2023, 13(4), 740; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings13040740 - 05 Apr 2023

Cited by 5 | Viewed by 1312

Abstract

An experimental test was performed to study the bond behavior between steel rebar and concrete reinforced by polyvinyl alcohol (PVA) fibers. Twenty specimens were prepared and subjected to the pull-out test. Four different fiber volume contents (0%, 0.2%, 0.4%, and 0.6%) were considered [...] Read more.

An experimental test was performed to study the bond behavior between steel rebar and concrete reinforced by polyvinyl alcohol (PVA) fibers. Twenty specimens were prepared and subjected to the pull-out test. Four different fiber volume contents (0%, 0.2%, 0.4%, and 0.6%) were considered and the concrete with the strength grade of C35 was designed in the present study. The effects of PVA fibers, rebar diameter, and cover depth on bond behavior were clarified. The effects of PVA fibers on the mechanical property of concrete were also studied. The results show that PVA fibers decreased the compressive strength of concrete, but increased splitting tensile, flexural, and direct tensile strength. PVA fibers negatively affected bonding in the ascending branch both for the pull-out and the splitting failure cases, but improved the bonding in the descending branch after peak stress for the splitting failure case. In the present test, the maximum decrement of bond strength was about 16.2% for specimens with less than 0.6% PVA fibers. PVA fibers restricted both the macro-cracking and micro-cracking for the splitting cases, the former were much more significant than the latter. The effects of rebar diameter and cover depth on bonding became slight and significant with the increasing content of PVA fibers, respectively. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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Review

Jump to: Research

24 pages, 2493 KiB

Open AccessReview

Application Research of Ultrasonic-Guided Wave Technology in Pipeline Corrosion Defect Detection: A Review

by Feng Lyu, Xinyue Zhou, Zheng Ding, Xinglong Qiao and Dan Song

Coatings 2024, 14(3), 358; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings14030358 - 18 Mar 2024

Viewed by 960

Abstract

This paper presents research on the application of ultrasonic-guided wave technology in corrosion defect identification, expounds the relevant ultrasonic-guided wave theories and the principle of ultrasonic-guided wave non-destructive testing of pipelines, and discusses the Lamb wave and shear horizontal wave mode selection that [...] Read more.

This paper presents research on the application of ultrasonic-guided wave technology in corrosion defect identification, expounds the relevant ultrasonic-guided wave theories and the principle of ultrasonic-guided wave non-destructive testing of pipelines, and discusses the Lamb wave and shear horizontal wave mode selection that is commonly used in ultrasonic-guided wave corrosion detection. Furthermore, research progress in the field of ultrasonic-guided wave non-destructive testing (NDT) technology, i.e., regarding transducers, structural health monitoring, convolutional neural networks, machine learning, and other fields, is reviewed. Finally, the future prospects of ultrasonic-guided wave NDT technology are discussed. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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62 pages, 10199 KiB

Open AccessEditor’s ChoiceReview

Electrochemical Detection of Hormones Using Nanostructured Electrodes

by Naila Haroon and Keith J. Stine

Coatings 2023, 13(12), 2040; https://0-doi-org.brum.beds.ac.uk/10.3390/coatings13122040 - 04 Dec 2023

Cited by 2 | Viewed by 2095

Abstract

Hormones regulate several physiological processes in living organisms, and their detection requires accuracy and sensitivity. Recent advances in nanostructured electrodes for the electrochemical detection of hormones are described. Nanostructured electrodes’ high surface area, electrocatalytic activity, and sensitivity make them a strong hormone detection [...] Read more.

Hormones regulate several physiological processes in living organisms, and their detection requires accuracy and sensitivity. Recent advances in nanostructured electrodes for the electrochemical detection of hormones are described. Nanostructured electrodes’ high surface area, electrocatalytic activity, and sensitivity make them a strong hormone detection platform. This paper covers nanostructured electrode design and production using MOFs, zeolites, carbon nanotubes, metal nanoparticles, and 2D materials such as TMDs, Mxenes, graphene, and conducting polymers onto electrodes surfaces that have been used to confer distinct characteristics for the purpose of electrochemical hormone detection. The use of aptamers for hormone recognition is producing especially promising results, as is the use of carbon-based nanomaterials in composite electrodes. These materials are optimized for hormone detection, allowing trace-level quantification. Various electrochemical techniques such as SWV, CV, DPV, EIS, and amperometry are reviewed in depth for hormone detection, showing the ability for quick, selective, and quantitative evaluation. We also discuss hormone immobilization on nanostructured electrodes to improve detection stability and specificity. We focus on real-time monitoring and tailored healthcare with nanostructured electrode-based hormone detection in clinical diagnostics, wearable devices, and point-of-care testing. These nanostructured electrode-based assays are useful for endocrinology research and hormone-related disease diagnostics due to their sensitivity, selectivity, and repeatability. We conclude with nanotechnology–microfluidics integration and tiny portable hormone-detection devices. Nanostructured electrodes can improve hormone regulation and healthcare by facilitating early disease diagnosis and customized therapy. Full article

(This article belongs to the Special Issue Advances in the Preparation and Characterization Techniques for Developing Coating Materials and Applications)

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