Corrosion Resistance Of Metals Research Articles

Diatomite@MoS2 Nanocomposite Layers as Composite Coating Targeting for Mg Alloys Endowed with Properties of Anticorrosion and Antiwear.

Molybdenum disulfide (MoS2) demonstrates promising applications in enhancing the corrosion and wear resistance of metals, but the susceptibility of this nanomaterial to agglomeration hinders its overall performance. In this study, the externally assisted corrosion inhibitor sodium molybdate (SM) was successfully constructed in diatomaceous earth (DE) and molybdenum disulfide (MoS2). This not only served as a molybdenum source for MoS2 but also enabled the preparation of DE@MoS2-SM microcapsules, achieving a corrosion inhibitor loading of up to 23.23%. The corrosion testing reveals that the composite coating, when compared to the pure epoxy coating, exhibits an impedance modulus 2 orders of magnitude higher (1.80 × 109 Ω·cm2), offering prolonged protection for magnesium alloys over a 40 day period. Furthermore, a filler content of 3% sustains a coefficient of friction (COF) at 0.55 for an extended duration, indicating commendable stability and wear resistance. The protective performance is ascribed to the synergistic enhancement of corrosion and wear resistance in the coatings, facilitated by the pore structure of DE, the high hardness of MoS2, and the obstructive influence of Na2MoO4. This approach offers a straightforward and efficient means of designing microcapsules for use in corrosive environments, whose application can be extended in industrial fields. In particular, we promote the application of nautical instruments, underwater weapons, and seawater batteries in the shipbuilding industry and marine engineering.

Pengaruh ketahanan korosi logam alumunium terhadap variasi pada larutan asam klorida 0,1 M dan 0,5 M

Background: Corrosion is a decrease in the quality of a material or metal to electrolyte reactions in the environment that affect the life of the material. Corrosion processes occur in acidic environments, sea water, rainwater, and soil are the result of chemical reactions that are also caused by electrochemical processes. The purpose of this study was to determine the corrosion resistance of aluminum metal to variations in 0.1 M and 0.5 M Hydrochloric Acid solution. This research uses an aluminum plate that will be immersed for 5 days with 0.1 M HCl and 0.5 M HCl solution. Methods: The method of data collection is by scanning Scanning Electron Microscopy (SEM) on each aluminum plate specimen that has been given corrosion treatment by heating at a temperature of 60 C HCl solution is one of the factors causing corrosion of metals. Finding: If in the free environment, air, temperature, and acidic substances are most commonly found as a factor causing corrosion. The increased corrosion rate is due to the higher concentration of the cause of corrosion. Conclusion: In this discussion, HCl as a concentration is used, and aluminum as a metal is tested.

A Cu-Ag double-layer coating strategy for stable and reversible Zn metal anodes

Structuring a stable artificial coating to mitigate dendrite growth and side reactions is an effective strategy for protecting the Zn metal anode. Herein, a Cu-Ag double-layer metal coating is constructed on the Zn anode (Zn@Cu-Ag) by simple and in-situ displacement reactions. The Cu layer enhances the bond between the Ag layer and Zn substrate by acting as an intermediary, preventing the Ag coating from detachment. Concurrently, the Ag layer serves to improve the corrosion resistance of Cu metal. During plating, the initial Cu sheets and Ag particles on the surface of Zn@Cu-Ag electrode gradually transform into a flat and smooth layer, resulting in the formation of AgZn, AgZn3, and (Ag, Cu)Zn4 alloys. Alloys play a multifunctional role in inhibiting dendrite growth and side reactions due to decreased resistance, low nucleation barrier, enhanced zincophilicity, and strong corrosion resistance. Consequently, the Zn@Cu-Ag symmetric cell exhibits continuous stable performance for 3750 h at 1 mA cm−2. Furthermore, the Zn@Cu-Ag||Zn3V3O8 full cell achieves an initial capacity of 293.4 mAh g−1 and realizes long cycling stability over 1200 cycles. This work provides new insight into the engineering of an efficient artificial interface for highly stable and reversible Zn metal anodes.

Technical operation factors influence on bus body durability

Introduction. The purpose of the work is to study the causes of corrosion destruction of bus bodies of the enterprise. In the course of work, it was revealed that the main causes of intensive corrosion destruction of bus bodies are insufficiently high corrosion resistance of metals used in the manufacture of the body frame. The main places of occurrence of foci of corrosion of the body are: wheel arches; rear and lower parts of the bus, which are more susceptible to adverse road conditions; the upper and lower parts of the window openings in case of violation of the tightness of the seal. In the course of the study, initial data were obtained to determine the conditions and factors determining condensation on the cooled surfaces of bus bodies entering the indoor parking area; a set of organizational and technical measures aimed at reducing the intensity of corrosion wear of the company’s vehicle bodies was developed.Materials and methods. The results of observations of changes in the technical condition of bus bodies, parameters of their maintenance conditions were used, methods of a priori ranking of factors and classification were used. The results and recommendations on the technical operation of bus bodies are described.Results. As intermediate results of the conducted research, the data on the influence of the technical condition of bus bodies on the indicators of technical operation were obtained, which make it possible to justify the modes of maintenance and storage of motor vehicles. The data obtained make it possible to simulate the processes affecting the technical condition of bus bodies, which is the basis for the development of optimization measures.Discussion. It is noted that the approach implemented during the study enables to establish a set of factors affecting the technical condition of bus bodies, and to determine the consequences of premature achievement of the limit state by the elements of the load-bearing structure.Conclusion. As a generalizing conclusion, it is noted that the practical implementation of the developed methodology ensures the development and implementation of sound measures to increase their durability in the practical activities of road transport enterprises.

Tribocorrosion studies on DLC films with silver nanoparticles for prosthesis applications

Metals and their alloys are very important for orthopedic applications, and the basic requirements for a successful implant are chemical stability, mechanical behavior, and biocompatibility in body fluids and tissues. For prosthesis applications, the corrosion resistance of metals is one of the major prerequisites to avoid impairment of the material properties due to degradation. The combined action of corrosion and wear on the material is called tribocorrosion and DLC (Diamond-Like Carbon) films have been extensively studied to increase prosthesis biocompatibility and to protect from corrosion. Additionally, DLC coatings can prevent the prosthesis to release toxic elements due to plastic deformation and corrosion. This paper is about tribocorrosion studies on DLC and DLC-Ag (DLC containing silver nanoparticles) on Ti-6Al-4V substrates. These films were obtained by PECVD (Plasma Enhanced Chemical Vapor Deposition) using hexane as a precursor. The tribocorrosion behavior of uncoated and coated samples was investigated in the reciprocating mode in Ringer’s lactate solution. From the polarization test results, the protective efficiency of the film was calculated. Silver nanoparticles improved the corrosion resistance of the films. The protective efficiency was 15 and 19% for DLC and DLC-Ag films, respectively.

Multifunctional coatings fabricated from Chinese hemp–derived superhydrophobic micro–nanocellulose

Ecologically feasible strategies for constructing superhydrophobic surfaces offer versatile applications in waterproofing, self–cleaning, selective absorption, and corrosion protection. Herein, we prepared low–surface–energy branched–chain–enriched micronanorod (F@SiO2@MNC) by hydrolyzing silane coupling agent and modifying fluoropolymer using micro–nanocellulose extracted from waste straw (Chinese hemp). These rods were sprayed and adhered to various substrates precoated with a binder, resulting in superhydrophobic surfaces. F@SiO2@MNC addition allowed for the formation of stable spherical liquid droplets when in contact with different types of aqueous liquids. Furthermore, these surfaces demonstrated excellent self–cleaning, robustness, abrasion resistance, UV resistance, cycling stability, and other multifunctionalities. They significantly enhanced the mechanical properties of filter paper, effectively separated oil water mixtures, and improved the corrosion resistance of metals. Our proposed strategy represents a novel approach for developing multifunctional coatings assembled from micronanocellulose.

Multiple Metal-Nitrogen Bonds Synergistically Boosting the Activity and Durability of High-Entropy Alloy Electrocatalysts.

The development of Pt-based catalysts for use in fuel cells that meet performance targets of high activity, maximized stability, and low cost remains a huge challenge. Herein, we report a nitrogen (N)-doped high-entropy alloy (HEA) electrocatalyst that consists of a Pt-rich shell and a N-doped PtCoFeNiCu core on a carbon support (denoted as N-Pt/HEA/C). The N-Pt/HEA/C catalyst showed a high mass activity of 1.34 A mgPt-1 at 0.9 V for the oxygen reduction reaction (ORR) in rotating disk electrode (RDE) testing, which substantially outperformed commercial Pt/C and most of the other binary/ternary Pt-based catalysts. The N-Pt/HEA/C catalyst also demonstrated excellent stability in both RDE and membrane electrode assembly (MEA) testing. Using operando X-ray absorption spectroscopy (XAS) measurements and theoretical calculations, we revealed that the enhanced ORR activity of N-Pt/HEA/C originated from the optimized adsorption energy of intermediates, resulting in the tailored electronic structure formed upon N-doping. Furthermore, we showed that the multiple metal-nitrogen bonds formed synergistically improved the corrosion resistance of the 3d transition metals and enhanced the ORR durability.

In-situ fabrication of Cr doped FeNi LDH on commercial stainless steel for oxygen evolution reaction

Commercial stainless steel has attracted increasing interest due to their rich content in transition metal elements and corrosion resistance properties. In this work, we design a facile and rapid route to in-situ fabricate the Cr doped FeNi layered double hydroxides nanosheets (LDHs) on modified stainless steel (Cr–FeNi LDH @ ESS) under ambient condition.The ultra small scaled 2D structure only around 20 nm diameter and metal ions with multivalent oxidation state were observed on the in situ fabricated LDHs, which provides high active area and active sites and thus promote excellent oxygen evolution reaction (OER). The Cr–FeNi LDH @ESS electrocatalysts exhibit an over potential of 280 mV at 10 mA cm−2 and achieves a Tafel slope of 44 mV dec−1 for OER in the 1.0 M KOH aqueous solution. We anticipate that the operating strategy of our system may promote the development of commercial non-precious productions as the efficient electrocatalysts for energy storage and conversion.

Influence of MC Carbides on Pitting Corrosion Resistance of Weld Metal in Austenitic Stainless Steels

Influence of MC Carbides on Pitting Corrosion Resistance of Weld Metal in Austenitic Stainless Steels

Performance enhancement of aluminium-gated poly(3-hexylthiophene) transistors with polymer electrolyte/PMMA bilayer gate dielectrics

Tremendous progress in device performance has been realized in electrolyte-gated field-effect transistors (FETs). However, due to the formation of oxides at the metal/electrolyte interface, electrochemically stable and corrosion-resistant noble metals (e.g., gold, platinum, or palladium) have been utilized, which makes device fabrication expensive. In this study, we report an enhanced performance in aluminium (Al)-gated poly(3-hexylthiophene) (P3HT) transistors with polymer electrolyte/poly(methyl methacrylate) (PMMA) bilayer gate dielectrics. This cost-effective Al-gated transistor devices with polymer electrolyte/PMMA bilayer dielectrics measured improved operational stability and hole mobility of ∼0.06 cm2 V−1 s−1 at low operating voltage of −15 V compared to the control Al-gated FETs with PMMA dielectric (∼0.03 cm2 V−1 s−1) and Al-gated devices with electrolyte dielectric (∼10−4 cm2 V−1 s−1). The exceptional performance in the FETs with bilayer gate dielectric would be attributed to an improved charge transport and a robust vacuum metalized Al/PMMA interface in contrast to the electrolyte-gated FETs, which was severely influenced by the formation of aluminium oxide layer (Al2O3) at the Al/dielectric interface. This study provides a practical approach for fabricating low-cost, low-voltage, and high-performance FET devices with hybrid polymer electrolyte/PMMA bilayer dielectrics.

Ultrathin Water-Responsive Zwitterionic Hydrogel Brush Coatings for Long-Term Corrosion Protection.

Preventing metal corrosion has usually been associated with water-repellent coatings that inhibit the penetration of aggressive chloride ions. Contrary to this conventional wisdom, we engineered ultrathin superhydrophilic zwitterionic hydrogel brushes rooted in a nanoporous anodic aluminum oxide (AAO) substrate that effectively hampered the adsorption of hydrated chloride ions (Cl-·H2O) on the Al alloy surface. The hydrogel brush coating enhanced corrosion resistance by 3 orders of magnitude, with corrosion current density declining from 1.518 to 1.567 × 10-3 μA cm-2. Despite suffering from long-term salt-spaying tests, zwitterionic hydrogel brush coating retained 2 orders of magnitude of corrosion resistance. Direct Raman spectroscopic evidence manifested that interfacial water comprised both highly ordered hydrogen-bonded water and disordered water containing hydrated Cl- ions. Under the hydration effect of zwitterionic hydrogel brushes, an interfacial disordered water structure dynamically transformed into a hydrogen-bonded water film. We correlated the structure and quantities of interfacial water with the corrosion current density and chloride adsorption. Hydrogen-bonded water improved by zwitterionic hydrogel brushes weakened the affinity and adsorption of hydrated Cl- ion water on the oxide film, resulting in excellent corrosion protection. Therefore, employing localized hydration tuning strategies, these findings are anticipated to generally empower ordered interfacial water to enhance metal corrosion resistance through precise interfacial engineering.

Optimization of Wire-bonding Process Parameters for Gold Wire and Aluminium Substrate using Response Surface Method

Wire bonding is a connecting technique that uses a combination of temperature, force, ultrasonic power, and time to attach two metallic materials, a wire, and a bond pad. In electronics, gold-aluminium (Au-Al) contact wire bonds are widespread due to corrosion resistance and great conductivity of both metals. However, due to the large contact-potential difference, the intermetallic compound growth at the metal’s interaction boundary has considerably worsened the advantageous properties of Au-Al intermetallic system. This intermetallic exhibit low toughness, and possibly low corrosion resistance, which would result in poor bonding quality. In this work, the materials used are 4x8 aluminium substrates and a 100-meter-long gold wire spool. This study aims to investigate the most optimised set of parameters to be used in Au-Al wire bond system, due to how problematic this system could have towards bonding quality. The experimental array was created using a response surface methodology (RSM)-based design of experiments. The effect of parameters and their significance to bonding quality in the Au-Al bond system were studied using analysis of variance (ANOVA). A correlation model was created for the wire bond strength data. The findings suggest that, within the range of parameters examined, the proposed correlation model can be utilized to predict performance measures. The optimum value of Au-Al wire bond system parameters was established at the time of bond at the first bonding site selected for 300 milliseconds (ms), wire looping height selected for 1200 micrometre (μm), wire bond Y-axis length selected for 996 micrometre (μm), and ultrasonic force at second bonding site selected for 300 milli Newton (mN). The outcomes of this research add to our understanding of the Au-Al wire bonding contact, in addition, to enhancing the wire bond's quality.

Elemental partitioning and corrosion resistance of Ni–Cr alloys revealed by accurate ab-initio thermodynamic and electrochemical calculations

Elemental partitioning during thermal processing can significantly affect the corrosion resistance of bulk alloys operating in aggressive electrochemical environments, for which, despite decades of experimental and theoretical studies, the thermodynamic and electrochemical mechanisms still lack accurate quantitative descriptions. Here, we formulate an ab initio thermodynamic model to obtain the composition- and temperature-dependent free energies of formation (ΔfG) for Ni–Cr alloys, a prototypical group of corrosion-resistant metals, and discover two equilibrium states that produce the driving forces for the elemental partitioning in Ni–Cr. The results are in quantitative agreement with the experimental studies on the thermodynamic stability of Ni–Cr. We further construct electrochemical (potential–pH) diagrams by obtaining the required ΔfG values of native oxides and (oxy)hydroxides using high-fidelity ab-initio calculations that include exact electronic exchange and phononic contributions. We then analyze the passivation and electrochemical trends of Ni–Cr alloys, which closely explain various oxide-film growth and corrosion behaviors observed on alloy surfaces. We finally determine the optimal Cr content range of 14–34 at%, which provides the Ni–Cr alloys with both the preferred heat-treatment stability and superior corrosion resistance. We conclude by discussing the consequences of these findings on other Ni–Cr alloys with more complex additives, which can guide the further optimization of industrial Ni–Cr-based alloys.

Strategy to Generate Oxide-Free Molten Metal Droplets for Fully Dense Corrosion-Resistant Coatings by Atmospheric Plasma Spraying

Thermal spray techniologies are very efficient to deposit metal coatings, which have been applied to different industrial fields for protection of metals from wear and corrosion. However, severe oxidation during inflight of spray particles introduces large amount of oxide inclusions in the coating which limits lamellar bonding formation and thus full utilization of coating material performance potential. In this project, the spray powders containing the deoxidizers such as carbon and boron are designed to develop in-situ deoxidizing effect to generate oxide-free molten metal droplets by air plasma spraying (APS) in ambient atmosphere for depositing dense coatings with sufficiently bonded splats. The thermodynamic and kinetic conditions for continuous deoxidization during whole in-flight molten droplets are presented. The experiments were conducted for NiCr, NiCrCu, CuNi coatings with boron as deoxidizer and for NiAl and FeAl coatings with dispersed diamond as deoxidizer. Results show that through powder design and spray condition optimization different spray particles can be heated to temperatures from 2100°C to 2500°C. It was found that the oxide contents in all coatings decreases with increasing spray distance, which indicates that deoxidizing effect of deoxidizer is maintained during whole spray particle in-flight. The examination shows that all APS coatings present dense microstructure. The electrochemical test reveals that the corrosion only occurs to coating surface and no trace of corrosive solution penetration into coating. As a result, the corrosion-resistant metal coatings can be realized by APS in ambient atmosphere through developing in-situ deoxidizing effect and subsequently oxide-free molten droplets with using deoxidizer-containing spray powders.

ANTI-CORROSION PROTECTION OF PIPELINES

Currently, in our country, the issue of protecting metals from corrosion has achieved high results, so there is a big gap between the achievements of scientific research in this direction and their use in industry. It is necessary to develop and implement highly effective methods of increasing the strength, corrosion resistance, heat and cold resistance of metals and alloys. Popularization, dissemination and implementation of effective methods of protection against corrosion and corrosive-mechanical destruction of machines, devices, equipment and metal structures are of great importance.
 During surface-plastic deformation, a chip is not formed, but a fine plastic deformation of the surface layer takes place. As a result, the surface layer is strengthened, wear resistance and resistance to corrosive environment increases. In many cases, the use of surface-plastic deformation makes it possible to increase the safety margin of parts working under variable loads by 1.5 to 3 times, and to increase the service life of parts. The paper examines directions for increasing the stability of parts of oil industry equipment by the method of surface plastic deformation, for resistance against various types of corrosion and corrosive-mechanical destruction.
 Fatigue is the phenomenon of gradual accumulation of material damage under the action of variable loads, which leads to changes in the properties of crack formation, their development and destruction. The processes of metal fatigue have been studied by many researchers, many hypotheses have been put forward, but the nature of fatigue remains largely unexplained.

Enhanced wear and corrosion resistance of the laser direct metal deposited AISI 316L stainless steel by in-situ interstitial N alloying

To meet the applicability in aggressive environments, the wear and corrosion resistance of additively manufactured 316L stainless steel can be improved by alloying with N. In this work, the in-situ interstitial N alloying of 316L with varying amount of CrxN is first manufactured at ambient environment utilizing the rapid cooling character of laser direct metal deposition (DMD). Combined effects of CrxN addition and DMD processing parameters on the relative density, dissolved N content, microstructure, microhardness, wear performance and corrosion behavior are systematically investigated. The results show that the relative density of the DMD 316L decreases with increasing additive amount of CrxN. A full density 316L sample with a high N content of 0.5 wt% is obtained. The N alloying transforms the solidification mode of DMD 316L from “AF” to “A”, resulting in a fully austenitic phase. The interstitial N promotes the formation of planar dislocations, nano-stacking faults and nano-twins during DMD. As the CrxN addition increases, both the microhardness (278–312 HV) and wear resistance are significantly enhanced owing to the dislocation strengthening and interstitial N solid solution strengthening. Compared with CrxN-free DMD 316L, the DMD 316L with CrxN addition presents superior pitting corrosion resistance. The increasing CrxN addition progressively improves the pitting corrosion resistance due to the positively synergistic effect Cr-N on the stability and repassivation ability of the passive film. This work provides a practical and cost-effective approach for manufacturing advanced 316L with exceptional properties.

Interface Analysis between Inconel 625 and Cobalt-Chromium Alloy Fabricated by Powder Bed Fusion Using Pulsed Wave Laser.

A few components used in the aerospace and petrochemical industries serve in corrosive environments at high temperatures. Corrosion-resistant metals or unique processes, such as coating and fusion welding, are required to improve the performance of the parts. We have used laser powder bed fusion (LPBF) technology to deposit a 5 mm thick corrosion-resistant CoCrMo layer on a high-strength IN625 substrate to improve the corrosion resistance of the core parts of a valve. This study found that when the laser volumetric energy density (EV) ≤ 20, the tensile strength increases linearly with the increase in EV, and the slope of the curve is approximately 85°. The larger the slope, the greater the impact of EV on the intensity. When EV > 20, the sample strength reaches the maximum tensile strength. When the EV increases from 0 to 20, the fracture position of the sample shifts from CoCrMo to IN625. When EV ≤ 38, the strain increases linearly with the increase in EV, and the slope of the curve is approximately 67.5°. The sample strain rate reaches the maximum when EV > 38. Therefore, for an optimal sample strength and strain, EV should be greater than 38. This study provides theoretical and technical support for the manufacturing of corrosion-resistant dissimilar metal parts using LPBF technology.

Improving the Protection Performance of Waterborne Coatings with a Corrosion Inhibitor Encapsulated in Polyaniline-Modified Halloysite Nanotubes

Organic coatings provide an effective way to improve the corrosion resistance of metals. Traditional organic varnishes, however, either contain highly polluting or toxic components or lack self-healing ability. In this article, we report a feasible method of preparing polyaniline-modified halloysite nanotubes (PANI@HNTs). They were loaded with a corrosion inhibitor, benzotriazole (BTA), and were tested as multifunctional anticorrosion additives for environmentally friendly epoxy waterborne coatings. The PANI@HNTs were formed via the in situ polymerization of aniline in the presence of halloysites. The BTA loading was then carried out and reached up to 14.5 wt.%. The BTA retention ability of the PANI@HNTs was significantly improved in comparison to that of pure HNT. Electrochemical impedance spectroscopy (EIS) tests of the coatings immersed in a 3.5 wt.% NaCl solution showed that the barrier and corrosion inhibition effects were enhanced by two to four orders of magnitude with the incorporation of BTA-loaded PANI@HNTs. The salt spray tests on artificially scratched coatings revealed that the surfaces protected by varnishes doped with the BTA-loaded PANI@HNTs exhibited the lowest degree of corrosion compared to the control samples, illustrating the self-healing potential of the modified coatings.

Additive Manufacturing for Powering the Blue Economy Applications: A Tidal Turbine Blade Case Study

As the marine renewable energy industry continues to expand, innovation in the manufacturing space must grow accordingly to reduce costs and ensure the economic feasibility of new technologies. Additive manufacturing, more commonly known as 3D printing, provides an alternative for rapid prototyping of marine hydrokinetic technologies, particularly supporting Powering the Blue EconomyTM initiatives of the U.S. Department of Energy Water Power Technologies Office. This study explores the application of additive manufacturing in the development of marine hydrokinetic structures, focusing on material and printing method selection, design, and analysis of a 3D-printed spar for an axial-flow tidal turbine blade. Corrosion-resistant metals were deemed ideal due to the loads and harsh marine environment the blade would experience. Laser metal deposition methods were determined to be the most effective and scalable for the considered scale. The designed spar adapts its geometry to the blade—a feature uniquely suited to additive manufacturing—and is intended to serve as the blade's primary structural component. A finite element model was used to study stresses and deformations under loading conditions. The spar was manufactured using 316L stainless steel through direct energy deposition, and defects were assessed and recorded. Future efforts will include mechanical testing of the spar. This research establishes a benchmark process for using additive manufacturing in developing marine hydrokinetic structures, paving the way for future optimization and techno-economic analysis.

Research on pulse laser cleaning and rust removal technology in power systems

In this paper, pulse laser cleaning and angle grinder polishing were used to clean the surface rust of carbon steel, and the cleaning effects of different cleaning methods for carbon steel surface rust were studied. The change of the micro-region morphology and element composition of the cleaned surface was analyzed. Comparative experiments were conducted on the corrosion resistance and paint anticorrosion ability of cleaned metal surfaces. Through comparison and analysis, the use of laser cleaning technology can improve the surface cleanliness and corrosion resistance of metals, reduce maintenance times, and extend service life. Laser cleaning machines with a power of 100 W or above can effectively perform precision cleaning and can be widely promoted in the field of power systems.