Corrosion Resistance Research Articles

Influence of hydrothermal time on anti-corrosion property of slippery liquid-infused porous surfaces on AZ31 magnesium alloys

To enhance anti-corrosion property of AZ31 magnesium alloys, slippery liquid-infused porous surfaces (SLIPSs) were prepared on benzoate-intercalated Mg-Al layered double hydroxides (LDHs). The typical morphology of SLIPSs was determined using a scanning electron microscope, and the successful loading of benzoate ions was confirmed by an X-ray diffractometer (XRD). Especially, this work focused on revealing how hydrothermal time affected the resistance to corrosion of SLIPSs. The electrochemical results indicated that when the hydrothermal duration was 24 h, the developed SLIPS exhibited remarkably improved corrosion resistance accompanied by the lowest corrosion current density of 2.5 × 10−3 μA cm−2. Furthermore, the results of immersion test demonstrated the superiority of SLIPSs in anti-corrosion durability. Based on the obtained results, the prepared SLIPSs can be promising candidates for the improvement in anti-corrosion performance of magnesium alloys.

Foaming mechanisms in ball milling prepared borosilicate glass powder

Thanks to their exceptional thermal and electrical properties, borosilicate glasses are widely used in chip packaging and electronic pastes. Nonetheless, borosilicate glass powders suffer from the phenomenon of foaming and expansion during sintering process, which greatly affects the sintering densities of the powders and poses limitations to their applications. Herein, we explored the foaming mechanism of borosilicate glasses by ball milling. The foaming of borosilicate glass is due to the adsorption of CO2 from the atmosphere by the glass powder during ball milling. The CO2 forms carbonates on the surface of the glass powder and is released during the sintering process, leading to foaming. Additionally, as the specific surface area of the glass powder increases, its corrosion resistance decreases while its foaming strength increases. The foaming strength of the four glass powders, listed in ascending order, is: SrO-B2O3-SiO2, ZnO-B2O3-SiO2, BaO-B2O3-SiO2 and CaO-B2O3-SiO2. Meanwhile, it was found that the foaming strength could be weakened better by ball milling organic modification method. These findings contribute to a deeper understanding of the glass foaming phenomenon. Furthermore, they offer practical strategies to reduce the foaming and optimize the performance of borosilicate glass-based materials in applications of chip packaging and electronic pastes.

Electrolyte Formulation with Improved Ion Desolvation and Diffusion Kinetics, and Superior Anti-Corrosion Properties for Ultrawide-Temperature Supercapacitors (–70∼100°C)

Electrochemical energy storage (EES) devices operating over a wide temperature range are crucial for extreme applications like near-space exploration (–70 °C) and desert exploitation (80 °C). However, their electrochemical performance is still hindered by the high-energy-barrier desolvation process at low temperature and the parasitic redox corrosion reactions at high temperature. In this work, an ultrawide-operating-temperature-window supercapacitor is proposed by simultaneously regulating ion kinetics of electrolyte and modulating anti-corrosion property of current collector. The optimized kinetics at low temperatures (–70 °C) refer to the enhanced ion dissociation and accelerated desolvation process, which is precisely regulated by the medium dielectric constant and low donor number of both methyl propyl ketone (MPK) and methyl ethyl ketone (MEK) cosolvents. Meanwhile, the remarkable cycling stability at high temperatures (100 °C) is realized by the strengthened corrosion resistance of carbon cloth current collector. The combination of MEK/MPK based electrolyte and carbon cloth current collector enables the supercapacitor to achieve a superior low-temperature capacitance retention (91.13 % @ –60 °C and 75.4 % @ –70 °C), extended high-temperature cycling stability (69.2 % @ 100 °C, 10,000 cycles) and excellent power and energy densities (13,820 W kg–1 @ 20.68 W h kg–1). This research is expected to provide valuable references for the advanced design of EES devices with wide-operating-temperature range in future studies.

Preparation and Characterization of Fluorinated Acrylate and Epoxy Co-Modified Waterborne Polyurethane

Conventional waterborne polyurethane (WPU) has poor water resistance and poor overall performance, which limits its application in outdoor coatings. A solution to this problem is urgently needed. The introduction of fluorine-containing groups can effectively improve the water resistance of WPU. In this study, a new fluorinated chain extender (HFBMA-HPA) synthesized by free radical copolymerization and epoxy resin (E-44) were used to co-modify WPU, and five waterborne fluorinated polyurethane (WFPU) emulsions with different fluorine contents were prepared by the self-emulsification method. The effects of HFBMA-HPA content on the emulsion particle properties, coating surface properties, mechanical properties, water resistance, thermal stability, and corrosion resistance were investigated. The results showed that the WFPU coating had excellent thermal stability, corrosion resistance, and mechanical properties. As the content of HFBMA-HPA increased from 0 wt% to 14 wt%, the water resistance of the WFPU coating gradually increased, the water contact angle (WCA) increased from 73° to 98°, the water absorption decreased from 7.847% to 3.062%, and the surface energy decreased from 32.8 mN/m to 22.6 mN/m. The coatings also showed impressive performances in the adhesion and flexibility tests in extreme conditions. This study provides a waterborne fluorinated polyurethane material with excellent comprehensive performance that has potential application value in the field of outdoor waterproof and anticorrosion coatings.

Selective laser melting of 2507 duplex stainless steel: Effect of energy density on microstructure and corrosion resistance

Duplex stainless steel (DSS) is widely used in the marine, petroleum, chemical, automotive, and other fields owing to its excellent mechanical properties and corrosion resistance. However, the research on duplex stainless steel prepared by additive manufacturing is still limited. In this paper, high-density 2507 DSS was successfully prepared by selective laser melting (SLM) additive manufacturing. The effects of energy density on the formability, phase composition, microstructure and corrosion properties of SLM 2507 DSS were investigated. The results showed that with the decrease of the energy density, the density of the specimen increases first and then decreases, and the density achieves 99.18% with the energy density of 190.5 J/mm3. The types of phases are not affected by the energy density, i.e., all 2507 DSS samples prepared by SLM showed a ferrite phase. The YOZ (parallel to the building direction) plane of the SLM 2507 DSS samples showed predominantly columnar grains attributed to the high temperature gradient and epitaxial growth characteristics. With the increase of energy density, the average grain size decreases slightly from 16.97 μm to 15.78 μm, the KAM value decreases slightly from 1.15 to 1.05, and the low angle grain boundaries (LAGBs) increase significantly from 68.4% to 74.8%. The SLM 2507 DSS sample exhibited excellent corrosion resistance. The self-corrosion potential of the sample is 136 mV and the self-corrosion current density is 2.066 × 10−8 A/cm2 at the maximum density. This investigation provides a new approach for the preparation of super duplex stainless steel, which can provide a theoretical basis and guidance for industrialized application.

Stability-enhanced (Cu-, Zn-)MOFs via (Cu, Zn)S composite strategy: A promising approach for oil-water separation

The application of metal-organic frameworks (MOFs) in the field of oil-water separation is developing rapidly, but the challenges of poor water stability, poor scalability and durability still limit its practical application. In this study, two environmentally friendly and non-toxic superhydrophobic (Cu, Zn)S/(Cu-, Zn-)MOFs@stearic acid (CuS/Cu-MOFs@SA and ZnS/Zn-MOFs@SA) coatings were successfully prepared by hydrothermal method combined with dip coating method, with a water contact angle (WCA) of >165°. Through the synergistic effect with stearic acid (SA), the (Cu-, Zn-)MOFs coating composited with CuS and ZnS exhibits excellent durability in extreme environments. This synergistic effect significantly improves the mechanical stability and durability of the coating, allowing it to maintain a WCA of >155° after friction, kneading, tape stripping and ultrasonic treatment. However, CuS/Cu-MOFs@SA coating is significantly superior to ZnS/Zn-MOFs@SA coating in terms of chemical stability (acid-base-salt environment) and self-cleaning ability due to the different ligands used in the preparation process and the formation of particle structure. Significantly improved its durability and reliability in oil-water separation. The separation efficiency of the coating is as high as 98.7 %, and it remains above 97.8 % after 12 times of repeated use. This study provides a new strategy and important reference for the development of superhydrophobic MOFs coatings and oil-water separation materials with high stability, wear resistance and corrosion resistance.

Very high cycle fatigue of austenitc stainless steels and their welds for reactor internals at ambient trmperature and 300 °C

The fatigue assessment of safety relevant components is of importance for ageing management with regard to safety and reliability of nuclear power plants. Austenitic stainless steels are often used for reactor internals due to their excellent mechanical and technological properties as well as their corrosion resistance. During operation reactor internals are subject to mechanical and thermo-mechanical loading which induce low cycle (LCF), high cycle (HCF) and even very high cycle (VHCF) fatigue. While the LCF behavior of austenitic steels is already well investigated the fatigue behavior in the VHCF regime has not been characterized in detail so far. Accordingly, the fatigue curves in the applicable international design codes have been extended from originally 106 to the range of highest load cycles up to 1011 load cycles by extrapolation. Nevertheless, the existing data base for load cycles above 107 is still highly insufficient. The aim of the cooperative project of the Institute of Materials Science and Engineering (WKK) at RPTU Kaiserslautern-Landau, Materials Testing Institute (MPA) Stuttgart and Framatome GmbH, Germany is to create a comprehensive database up to the highest load cycles N = 2·109 for austenitic stainless steels and their welds at ambient and elevated temperature.

Conceptual design of a prestressed precast UHPC-steel hybrid tower to support a 15 MW offshore wind turbine

Ultra-high-performance-concrete (UHPC) possesses favorable mechanical properties and economy efficiencies and has the potential to be used as the main material to construct tower structures of offshore wind turbines (OWTs). Then the shortages of widely used pure steel OWT towers such as relatively small lateral stiffness, weak fatigue behavior and corrosion resistance can be avoided. In this work, a new type of hybrid tower structure combining a prestressed UHPC tube at the bottom and an upper steel tube is proposed to support a large-size 15 MW OWT. Detailed and carefully refined finite element (FE) analysis by ABAQUS was conducted to explore the dynamic performance of the proposed hybrid tower. The modal properties, dynamic responses, ultimate strength, fatigue strength, and economy performance of the hybrid tower were comprehensively evaluated. It shows that with a similar lateral stiffness but greatly reduced material and maintenance costs compared to a reference steel tower, the hybrid tower has enough ultimate and fatigue strength to resist huge environmental loads caused by extreme winds, waves and earthquakes.

Influence of the Metallic Sublayer on Corrosion Resistance in Hanks’ Solution of 316L Stainless Steel Coated with Diamond-like Carbon

Influence of the Metallic Sublayer on Corrosion Resistance in Hanks’ Solution of 316L Stainless Steel Coated with Diamond-like Carbon

Model construction of corrosion resistance of alloying elements for low alloy steel in marine atmospheric corrosive environment based on machine learning

Model construction of corrosion resistance of alloying elements for low alloy steel in marine atmospheric corrosive environment based on machine learning

Investigations on mechanical and surface properties of friction stir welded dissimilar joints of 2507 SDSS and 317L ASS

Friction stir welding (FSW), recognized as an eco-friendly and safe welding technique, finds widespread application across industries including aerospace, and automotive sectors. As a key material in production, stainless steel (SS) has great application potential in FSW. In this article, solid-state joining of dissimilar materials 2507 super duplex stainless steel (SDSS) and 317 L austenitic stainless steel (ASS), using FSW was investigated. By adjusting the position of 2507 SDSS and 317 L ASS, this paper examined the mechanical and surface properties of the joints at rotation speed of 400 rpm and welding speed of 20 mm/min. The results revealed that alteration of the material position seemed to have negligible influence on the joint's appearance, tensile behavior, and failure location. However, a clear grain refinement post-FSW in the joints was recorded, leading to a substantial increase in the hardness of the center stir zone (CSZ), alongside noticeably enhanced wear resistance. This grain refinement also contributed to an improvement in the corrosion resistance of the joints.

Enhanced Corrosion Resistance of CuAl/BN Coatings through the Addition of Rare Earth Elements and High-Temperature Oxidation Treatment

Enhanced Corrosion Resistance of CuAl/BN Coatings through the Addition of Rare Earth Elements and High-Temperature Oxidation Treatment

One-Step Air Spraying of Structural Coating on Cu Alloy as Superhydrophobic Surface for Enhanced Corrosion Resistance and Anti-Icing Performance

One-Step Air Spraying of Structural Coating on Cu Alloy as Superhydrophobic Surface for Enhanced Corrosion Resistance and Anti-Icing Performance

Improvement of Tribological Properties and Corrosion Resistance of AISI 4340M Steel by Shot Peening and Plating Technologies

Improvement of Tribological Properties and Corrosion Resistance of AISI 4340M Steel by Shot Peening and Plating Technologies

Enhancing Thermal Stability and Corrosion Resistance of Carbon-Carbon Composites with Iridium Coatings Deposited by Electron Beam Physical Vapor Deposition

Enhancing Thermal Stability and Corrosion Resistance of Carbon-Carbon Composites with Iridium Coatings Deposited by Electron Beam Physical Vapor Deposition

Biomimetic (Co, Ni, W)OxNy/WO3 photoelectrocatalyst for robust seawater oxidation

As an intriguing strategy for massive hydrogen production, photoelectrochemical (PEC) seawater splitting compels the anode to be highly hypochlorite-resistant. Inspired by algae, we designed a robust photoelectrocatalyst that WO3 nanorods (NRs) are covered by N/W co-doped (Co, Ni, W)OxNy nanosheets (NSs). The NSs expose (111) faces and are decorated by (Co, Ni)WO4 nanoparticles. DFT calculations reveal that Co and Ni atoms on the (111) surface of N/W co-doped NSs are more likely to adsorb OH-, while W atoms are more favorable to adsorb Cl-. Secondly, the lattice distortion and multi-crystal phases of NSs are triggered by doped W atoms, and the evacuation of 5d electrons makes W atoms as donor centers, leading to enhanced catalytic activity of CoNi atoms and corrosion resistance to Cl-. Furthermore, the N atoms expand the valence band of CoNiOx and elevate the conduction band of (Co, Ni)WO4, facilitating more electrons to participate in PEC reaction and the realization of seawater full-splitting. Resultantly, the N/W co-doped (Co, Ni, W)OxNy/WO3 hetero-NRs (HNRs) demonstrate a PEC current density about 0.35 mA/cm2 at 1.23 VRHE with durability over 100 hours in seawater. This work provides a practical strategy towards the durable PEC anode for seawater splitting.

Effect of multi-element synergistic addition on the microstructure evolution and performance enhancement of laser hot-wire cladded Fe-based alloy

To satisfy the requirements of hardness and corrosion resistance for laser additive manufacturing of hydraulic supports, this study applied the synergistic addition of C, B, Cr, Ni, Nb and Mo elements in Fe-based alloys. The multi-phases, martensite + austenite + ferrite were designed. The microstructure, hardness and corrosion resistance of the coatings were analyzed. Increasing the C and B contents could significantly increase the hardness of the coatings, while the corrosion resistance was decreased. The corrosion resistance of the coatings was determined by the Cr contents. However, increasing the Cr contents to 20.0 wt % resulted in the ferrite structure with lower hardness (21 HRC). The coatings with 0.25 wt % C, 1.2 wt % B and 19.0 wt % Cr showed the optimal matching of hardness (56 HRC) and corrosion resistance (survived in neutral salt spray test≥300h). The resulted coatings were mainly consisted of dendritic structure. Fine lath martensite phase was dominant in the dendrite regions. The interdendritic regions were consisted of nano-sized intermetallics with a mixture of σ+Nb + FeNb + Cr2Nb+(Fe,Cr)2B + NbC compounds. These interdendritic regions (14.2 GPa) showed higher hardness than that of the dendritic regions (7.1 GPa). The high Cr contents with finer dendritic structures were the major mechanisms for the excellent combination of hardness and corrosion resistance. The precipitation and growth mechanisms of the interdendritic phases were elaborated. This work provides a valuable reference for laser hot-wire cladding to prepare Fe-based alloys with high hardness and excellent corrosion resistance.

Effect of intermittent non-isothermal aging on the microstructure and properties of Al–Zn–Mg–Cu alloy

The proposition of an intermittent non-isothermal aging (IM-NIA) is an innovative approach to address the challenge of balancing the mechanical properties and corrosion resistance of Al–Zn–Mg–Cu alloys. The effects of IM-NIA on the hardness, corrosion resistance and microstructure morphology of Al–Zn–Mg–Cu alloys were investigated by hardness test, intergranular corrosion test (IGC), exfoliation corrosion test (EXCO), electrochemical corrosion test and combined with transmission electron microscopy (TEM) observation. The results showed that the hardness of the alloy was the highest at 186HV after intermittent post-tempering to 180 °C (IM-H180). The intergranular corrosion depth is the smallest, the corrosion rate is the slowest, and the exfoliation corrosion rating is EA. In addition, the alloy matrix precipitated phase has the smallest average diameter, the highest volume fraction, the strongest ability to repair the passivation film, and the strongest resistance to Cl− erosion; At the same time, the grain boundary precipitation phase is intermittent and multilinear parallel distribution, PFZ is the widest, hindering the anodic corrosion channel, slow corrosion progress and improve corrosion resistance.

Insights into the role of tungsten on corrosion behavior of high-strength Ti alloys

High-performance titanium alloys with good corrosion resistance are expected to be applied in marine environments. In this work, we developed a Ti20W alloy using powder metallurgy and hot extrusion, which combined remarkable mechanical properties and good corrosion resistance. The Ti20W alloys exhibited ultrahigh strength (>1400 MPa) and good ductility (>7%), and the specific yield strength was comparable to the common high-strength Ti alloys. The ultrahigh-strength Ti20W alloys had characteristics of the solid solution of W atoms and the precipitation of fine α phases. Compared with Ti6Al4V alloy, the Ti20W alloys showed lower corrosion current density values in 3.5 wt% NaCl solution, which was attributed to the solid solution of W elements and the finer α phases. The W oxides, particularly WO3, acted as the barrier to effectively block the penetration of Cl− into the inner oxide layer, thereby enhancing the corrosion resistance. The fine α phases could be bridged by the surrounding matrix oxides during the passivation process, which contributed to decreasing the galvanic corrosion between the α phases and the matrix, further improving the corrosion resistance.

Zr-based conversion film fabricated on cold rolled steel by separately providing zirconium and fluorine ions: Performance and mechanism study

Controlling the concentrations of Zr4+ and F− in traditional Zirconium (Zr)-based film-formation solution is challenging due to their dependence on the hydrolytic equilibrium of H2ZrF6. In this study, Zr-based films were prepared on cold rolled steel surface through the film-formation solution prepared by mixing Zr(NO3)4 and different amount of HF. The electrochemical results demonstrated that the Zr-based film prepared by Zr(NO3)4 and HF exhibited superior corrosion resistance compared to H2ZrF6. Under optimal film formation conditions, the protective efficiency of the prepared film reached 74.4 % which was higher than that of film fabricated in H2ZrF6. The electrochemical results concurrently demonstrated the self-reinforcing anti-corrosion performance of the prepared films. Scanning electron microscopy revealed that the Zr film, prepared in Zr(NO3)4 and HF, exhibited excellent corrosion resistance attributed to its high film density. The X-ray photoelectron spectroscopy and energy dispersive spectroscopic results indicated the presence of a fluoride layer on the surface of the Zr film. The F− ions can chelate with the corrosion products and selectively deposit onto the damaged areas of the film, thereby effectively contributing to the repair of the film layer. The results of density functional theory calculations demonstrated that Zr4+ readily forms Zr(OH)4 rather than ZrF62−. The present study offers an enhanced approach for regulating the properties of films prepared via H2ZrF6 by separately providing zirconium and fluorine ions.