Showing papers on "Corrosion published in 2019"

Corrosion of Metallic Biomaterials: A Review

Abstract: Metallic biomaterials are used in medical devices in humans more than any other family of materials. The corrosion resistance of an implant material affects its functionality and durability and is a prime factor governing biocompatibility. The fundamental paradigm of metallic biomaterials, except biodegradable metals, has been “the more corrosion resistant, the more biocompatible.” The body environment is harsh and raises several challenges with respect to corrosion control. In this invited review paper, the body environment is analysed in detail and the possible effects of the corrosion of different biomaterials on biocompatibility are discussed. Then, the kinetics of corrosion, passivity, its breakdown and regeneration in vivo are conferred. Next, the mostly used metallic biomaterials and their corrosion performance are reviewed. These biomaterials include stainless steels, cobalt-chromium alloys, titanium and its alloys, Nitinol shape memory alloy, dental amalgams, gold, metallic glasses and biodegradable metals. Then, the principles of implant failure, retrieval and failure analysis are highlighted, followed by description of the most common corrosion processes in vivo. Finally, approaches to control the corrosion of metallic biomaterials are highlighted.

Solar-driven, highly sustained splitting of seawater into hydrogen and oxygen fuels

Abstract: Electrolysis of water to generate hydrogen fuel is an attractive renewable energy storage technology. However, grid-scale freshwater electrolysis would put a heavy strain on vital water resources. Developing cheap electrocatalysts and electrodes that can sustain seawater splitting without chloride corrosion could address the water scarcity issue. Here we present a multilayer anode consisting of a nickel–iron hydroxide (NiFe) electrocatalyst layer uniformly coated on a nickel sulfide (NiSx) layer formed on porous Ni foam (NiFe/NiSx-Ni), affording superior catalytic activity and corrosion resistance in solar-driven alkaline seawater electrolysis operating at industrially required current densities (0.4 to 1 A/cm2) over 1,000 h. A continuous, highly oxygen evolution reaction-active NiFe electrocatalyst layer drawing anodic currents toward water oxidation and an in situ-generated polyatomic sulfate and carbonate-rich passivating layers formed in the anode are responsible for chloride repelling and superior corrosion resistance of the salty-water-splitting anode.

Utilizing Lemon Balm extract as an effective green corrosion inhibitor for mild steel in 1M HCl solution: A detailed experimental, molecular dynamics, Monte Carlo and quantum mechanics study

Abstract: This study concerns with mild steel corrosion inhibition in 1M HCl solution protected with different concentrations of Lemon Balm extract. Electrochemical and theoretical approaches are utilized for approaching this goal. The type of functional groups in the active components present in the Lemon Balm extract (LB.E) was examined through UV–visible analysis, Fourier Transform Infrared (spectroscopy) (FT-IR) and Raman spectroscopy. According to the electrochemical impedance spectroscopy (EIS) test results the maximum inhibition efficiency of about 95% was obtained in the solution containing 800 ppm LB.E. Potentiodynamic polarization test results revealed that in the presence of LB.E the rates of anodic steel dissolution and cathodic hydrogen evolution reactions significantly decreased and a mixed inhibition effect was obtained. Surface studies were done by contact angle test, atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results revealed that the steel surface damage as a result of HCl solution attack significantly decreased by addition of 800 ppm LB.E. In addition, deposition of a highly hydrophobic film composed of organic compounds of inhibitors on mild steel surface was demonstrated by contact angle test results. The excellent corrosion inhibition effect of LB.E on mild steel in HCl solution is related to the adsorption of active inhibitive compounds such as caryophyllene, germacrene, citral, luteolin, chlorogenic acid and rosmarinic acid on the anodic/cathodic places of mild steel surface. Furthermore, the theoretical results derived from Monte Carlo, molecular dynamics and quantum mechanics techniques evidenced the inhibitors adsorption onto steel substrate through donor-acceptor interactions.

Characterization of Al-7075 metal matrix composites: a review

Abstract: Aluminum-7075 series alloys commonly used in transportation applications are aerospace, aviation, marine and automobile due to their good mechanical properties and low density and high strength-to-density ratio [1] . The present review focuses on mechanical properties, tribological properties and corrosion behavior of Al-7075 metal matrix composites (AMMCs) by the addition of desirable reinforcements. The objective is to review the literature on fabrication of the aluminum metal matrix composite materials by combining alloys and reinforcements. The reinforcements may be particulate SiC, Al2O3, Gr, TiO2, bagasse ash, etc. These particulate reinforcements are incorporated in the stir casting method. The results revealed that, there is significant improvement in mechanical properties. Superior wear and corrosion resistance, low coefficient of thermal expansion as compared to conventional base alloys.

A review of electrodeposited Ni-Co alloy and composite coatings: Microstructure, properties and applications

Abstract: Ni Co alloy electrodeposits have been widely employed in industry due to their good corrosion and wear resistance, high mechanical strength, moderate thermal conductivity and outstanding electrocatalytic and magnetic properties. This review aims to provide an insight into the mechanism of electrodeposition and effect of operational parameters and deposit microstructure, together with the mechanical, electrochemical and tribological characteristics of Ni Co alloys and included particle, composite deposits. Potential applications of the coatings have also been considered in applications as diverse as additive manufacturing, micro-tools, micro-sensors, electronic imaging and electrochemical energy conversion.

Myristic acid based imidazoline derivative as effective corrosion inhibitor for steel in 15% HCl medium.

Abstract: There is a high demand of effective and eco-friendly corrosion inhibitor for industrial applications. In an attempt to prepare a benign and effective corrosion inhibitor for acidizing purpose, an imidazoline derivative, N-(2-(2-tridecyl-4,5-dihydro-1H-imidazol-1-yl)ethyl)tetradecanamide (NTETD) was synthesized from myristic acid and diethyleneamine. The characterization of the newly synthesized compound was done using 1H NMR, FTIR, and elemental analysis techniques. NTETD was examined as a corrosion inhibitor for low carbon steel in 15% HCl solution using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), linear polarization (LPR), scanning electron microscope (SEM), energy dispersive spectroscopy (EDAX), atomic force spectroscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. It was found that, the optimum concentration of NTETD is 300 mg/L. With this concentration, inhibition efficiency above 93% is achievable. Results from PDP show that, NTETD acted as a mixed type corrosion inhibitor but with principal effect on cathodic corrosion half reactions. The calculated value of the adsorption-desorption equilibrium constant (1.015 × 103) reveals a strong bonding between NTETD molecules and the steel surface. The EDAX, FTIR, and XPS results confirm the adsorption of NTETD molecules on the steel surface. SEM and AFM results agree with experimental findings that NTETD is effective in corrosion mitigation of steel in 15% HCl solution. The possible corrosion inhibition mechanism by NTETD has been proposed.

High-performance oxygen evolution electrocatalysis by boronized metal sheets with self-functionalized surfaces

Abstract: The oxygen evolution reaction (OER) is a key half-reaction involved in many important electrochemical reactions, but this process is quite sluggish and the materials needed usually show unsatisfactory activity, stability or corrosion resistance in the harsh electrocatalysis environment. Here we report an effective boronization strategy for the value-added transformation of inexpensive, commercially available metal sheets (Ni, Co, Fe, NiFe alloys and steel sheets) into highly active and stable, corrosion resistant oxygen evolution electrodes. The boronized metal sheets exhibit OER activities that are an order of magnitude higher than those of the corresponding metal sheets, and show significantly improved catalytic stability and corrosion resistance in the operating environment. The in situ formed, ultrathin (2–5 nm), metaborate-containing oxyhydroxide thin films on metal boride surfaces are identified as a self-functionalized, highly active catalytic phase for the OER. In particular, a boronized NiFe alloy sheet is demonstrated to exhibit intrinsic catalytic activity higher than those of the state-of-the-art materials in 1 M KOH, while retaining such catalytic activity for over 3000 hours. Additionally, the boronized NiFe alloy and steel sheets are also demonstrated to have good catalytic activity as well as excellent catalytic stability and corrosion resistance in 30% KOH solution, a widely-adopted electrolyte in commercial water–alkali electrolyzers.

Experimental investigation on mechanical properties of AA7075-AlN composites

Abstract: Hard ceramic particle reinforced aluminum matrix composites (AMCs) are considered a distinct category of advanced materials which command outstanding strength, good corrosion resistance an...

Corrosion of metallic materials fabricated by selective laser melting

Abstract: Additive manufacturing is an emerging technology that challenges traditional manufacturing methods. However, the corrosion behaviour of additively manufactured parts must be considered if additive techniques are to find widespread application. In this paper, we review relationships between the unique microstructures and the corresponding corrosion behaviour of several metallic alloys fabricated by selective laser melting, one of the most popular powder-bed additive technologies for metals and alloys. Common issues related to corrosion in selective laser melted parts, such as pores, molten pool boundaries, surface roughness and anisotropy, are discussed. Widely printed alloys, including Ti-based, Al-based and Fe-based alloys, are selected to illustrate these relationships, and the corrosion properties of alloys produced by selective laser melting are summarised and compared to their conventionally processed counterparts.

Organic green corrosion inhibitors (OGCIs): a critical review

Abstract: Abstract Over the decades, corrosion has resulted in loss of lives accorded with damage costs in almost all engineering fields. Thus, it is seen as an environmental threat with catastrophic attributes, which calls for day-to-day research on its final resolution. Recent studies have proven organic green corrosion inhibitors (OGCIs) from plant extracts with biodegradable, environmentally accommodative, relatively cheap, and nonharmful features as the most perfect approach of tackling the problem. This review gives succinct discussion on the mechanisms, classifications, and active functional groups of OGCIs. Measuring ways and factors influencing their efficiency are presented. Also, various plant extracts used as OGCIs in preventing material corrosion in corrosive media coupled with their respective findings, applied characterization techniques, and future challenges are presented. The significance of values obtained from simulating presented mathematical models governing OGCI kinetics, adsorption isotherm, and adsorption thermodynamics is also included. In conclusion, recommendations that will broaden the usage of OGCIs from plant extracts for inhibiting corrosion of materials are presented for prospective researchers in the field of corrosion.

High-entropy environmental barrier coating for the ceramic matrix composites

Abstract: A novel high-entropy material, (Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7 ((5RE0.2)2Si2O7) was prepared by the sol-gel method and investigated as a promising environmental barrier coating (EBC) for SiC-based composites. The results of X-ray diffraction and transmission electron microscopy indicated that rare-earth elements were distributed homogeneously in the single monoclinic phase. Moreover, it was found that the new material (5RE0.2)2Si2O7 had good phase stability, well-matched coefficient of thermal expansion with SiC-based composite, and excellent resistance to water-vapor corrosion. The water-vapor corrosion test of (5RE0.2)2Si2O7 coated Cf/SiC composites further confirmed that (5RE0.2)2Si2O7 was suitable for application as EBC material and could provide effective protection to Cf/SiC composites from water-vapor damage.