Electrochemical Corrosion Behavior Research Articles

Corrosion, surface, and tribological behavior of electrophoretically deposited polyether ether ketone coatings on 316L stainless steel for orthopedic applications

Electrophoretic deposition (EPD) of polyether ether ketone (PEEK) coatings on metallic implants has recently attracted a great deal of interest; however, further investigation into their corrosion, surface, and tribological properties is required for their clinical application. Using Potentiodynamic polarization and Mott-Schottky analysis of PEEK coatings, we analyzed the electrochemical corrosion behavior of electrophoretically deposited PEEK coatings on 316L stainless steel (SS) substrates. In addition, the tribological behavior of the coatings was determined through pin-on-disc and scratch testing. Initially, the EPD parameters were optimized using a Taguchi Design of Experiment (DoE) approach. The coatings exhibited irregular shaped grains along with ∼66 μm of thickness. Fourier transform infrared spectroscopy confirmed the presence of functional groups ascribed with PEEK. The coatings were moderately hydrophobic and had an average roughness of ∼2 μm. The corrosion studies demonstrated promising features of current density and corrosion potential, indicating that corrosion resistance significantly improves with PEEK coating. Electrochemical impedance spectroscopy also confirmed the corrosion resistance of PEEK coating. The coatings exhibited a slightly lower wear resistance than SS samples, but still possessed adequate wear and scratch resistance for biomedical applications. The current study confirmed that the PEEK coatings on metallic implants is effective for orthopedic applications where corrosion and tribology are major concerns.

Prediction of electrochemical corrosion behavior of magnesium alloy using machine learning methods

The corrosion of magnesium (Mg) alloys is a major challenge in many industrial applications because of their extreme reactivity, this greatly limits their applicability. The traditional methods in the prediction of corrosion rate depend on experimental or empirical models that can be time-consuming and expensive. Besides how to integrate experiments with faster machine-learning approaches is still a challenge of research. In recent years machine learning (ML) algorithms have proved and promised better magnesium corrosion predictability. In this study, different training algorithms such as linear regression (LR), decision tree (DT), extra tree (ET), random forest (RF), K-nearest neighbor (KNN), extreme gradient boosting (XGBoost), and Artificial Neural Network (ANN) were used to develop and predict corrosion rate of magnesium alloys based on magnesium chemical alloy composition as independent input variables. The data used for model preparation and validation were obtained from literature and experimental studies respectively. The feature selection methods were used to identify the most important and influential input parameters for magnesium alloy thus Shapley Additive Explanations (SHAP) interpretation was employed in this manuscript to facilitate feature visualization of the model. The results of the study show that the random forest (RF) algorithm has the greatest prediction impact than other machine learning algorithms. The magnesium alloy corrosion prediction model provides a better ability for the prediction of magnesium corrosion alloys. The study demonstrates the potential of ML models in the prediction of the corrosion behavior of Mg alloys and these models can be used to optimize an alloy composition for designing improved corrosion resistance of new Mg alloys.

Influence of laser shock peening on surface characteristics and corrosion behavior of zirconium alloy

Low energy laser shock peening (LE-LSP) with different energies was carried out at zirconium (Zr) alloy. Characterization and electrochemical corrosion behavior of Zr alloy after LE-LSP treatment were investigated. Results show that the surface profile of Zr alloy after LE-LSP treatment is rough due to the regular undulations on the surfaces. The hardness of Zr alloy increases after LE-LSP treatment because the grain size of Zr alloy is refined, and the plastic deformation generated on the surface induces the working hardening. A melting layer, plastic deformation layer, and transition layer are formed on Zr alloy after LE-LSP treatment. The dislocation entanglement is observed at the plastic deformation layer, which indicates that the dislocation slip is the main deformation mechanism of Zr alloy. The electrochemical corrosion resistance of Zr alloy after LE-LSP treatment is improved because of an increase in the grain boundary, which improves the activity of Zr alloy and is beneficial for forming passive films.

Wear and corrosion behavior of vanadium-alloyed nodular cast irons fabricated by sand-casting

Nodular cast irons have been mainly used in automobile components exposed to large forces like brake pads, suffering from abrasion against recently developed lightweight Al2O3-containing brake rotors during operation. Besides, aqueous corrosion (rain, snow, and chlorides) can cause these brake pads to wear out faster. This study examined the wear and corrosion properties of the V-alloyed nodular cast irons as a function of V content (0, 0.25, 0.5, 0.75, and 1 wt%). The samples were tested against an Al2O3 ball to simulate more severe abrasive conditions, whereas the electrochemical corrosion behavior was investigated in a 3.5 wt% NaCl solution. It was revealed that wear resistance increased with increasing V up to 0.50 wt%, but higher V caused a reduction due to the heavily branched eutectic carbide formation. Wear losses increased with the applied load, whereas sliding speed had no significant effect. The samples experienced uniform and graphitic corrosion in a 3.5 wt% NaCl environment. Increasing V improved their corrosion resistance to 0.75 wt% V due to the precipitated spherical vanadium carbides. The 1 wt% V-alloyed sample failed both wear and corrosion tests because of increased metastable eutectic carbides.

Electrochemical corrosion behavior of powdered superalloy René 88DT in NaCl-glycol electrolyte and its aging effects

Electrochemical corrosion behavior of powdered superalloy René 88DT in NaCl-glycol electrolyte and its aging effects

Electrochemical corrosion behavior and in vitro biocompatibility of Ti-Nb-Sn alloy for dental applications

Ti-Nb-Sn alloy was prepared by mechanical alloying and mold sintering process, and the effects of Nb on the microstructure, corrosion behavior and in vitro biocompatibility were investigated. With the increased Nb content, the microstructure was transformed from Widmannstatten to needle-like structure. Moreover, the stable passivation films of TiO2, Nb2O5 and SnO2 were formed on the surface of the alloy in artificial saliva, and the surface wettability was changed from hydrophilic to hydrophobic, which made the corrosion resistance of the alloy was intensified. The increase of Nb content can promote adhesion and proliferation of mouse osteoblasts, and accordingly improve cell vitality.

Influence of Bioactive Glass Addition on TC4 Laser Cladding Coatings: Microstructure and Electrochemical Properties

There is a growing interest in enhancing the bioactivity of TC4-based metallic biomaterials, which are known for their excellent biocompatibility. Bioactive glass (BG) has been recognized for its high potential in promoting bioactivity, particularly in osteo tissue engineering. This study focuses on investigating the influence of BG addition on the microstructure and electrochemical properties of TC4 coatings. The TC4/BG composite coatings were fabricated through laser cladding, and their microstructure was characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The electrochemical properties of the coatings were assessed through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in three different solutions. The results revealed that the incorporation of BG had a significant impact on the microstructure of the TC4 coatings, leading to the formation of a well-defined interface between the TC4 matrix and the BG aggregates. The distribution of BG aggregates within the TC4 matrix coating was found to be random and unrelated to the specific regions of the coating. The metallographic microstructure variations were attributed to different heat dissipation conditions during the laser cladding process. Furthermore, the electrochemical corrosion behavior of TC4/BG composite coatings reveals that they exhibit stability similar to that of passive films and good resistance against media corrosion compared to TC4, while also showing enhanced corrosion resistance in 3.5 wt% NaCl and Dulbecco’s modified Eagle medium (DMEM) solutions, indicating their potential for biomedical applications; however, the corrosion resistance decreases gradually in all solutions, potentially due to the elevated Cl− concentration. Further research can explore bioactivity enhancement of TC4/BG composite coatings and investigate the long-term stability and biological response of these coatings in diverse physiological environments.

Effect of substrate orientations on the electrochemical and localized corrosion behavior of a quad-layer Al alloy composite

Electrochemical and localized corrosion behavior of a 4045/7072/3003 M/4045 Al alloy composite in 3.5 wt.% NaCl solution was investigated from cross-sectional and plane directions by electrochemical impedance spectroscopy, polarization curves, and high-resolution microscopic examination. Plane directions showed higher corrosion resistance than the cross-sectional surface, with almost all localized corrosion initiated from Si-containing inclusions. The cross-section showed a complex galvanic effect among the four layers, the galvanic coupling between 4045/7072 accelerated the dissolution of 7072 because 7072 served as the anode, however, the galvanic coupling between 3003 M/4045 protected 4045 from corrosion, indicating that 3003 M served as the anode.

Electrochemical corrosion behavior and theoretical simulation of cobalt in chemical mechanical polishing process

The chemical mechanical polishing (CMP) process for cobalt (Co) interconnects is essential for the fabrication of integrated circuits with feature sizes below 10 nm. However, achieving high removal rates coupled with low dissolution rates remains a significant challenge. In this work, we have developed a dual-functional polishing slurry, which integrates ethylenediamine tetramethylphosphonic acid (EDTMPA) as a complexing agent, and octahydroxamic acid (OHA) as a corrosion inhibitor. The novel slurry-derived Co CMP meets ideal situation, delivering a removal rate (RR) of 246 nm/min, a dissolution rate (DR) of 0.8 nm/min, and a root mean square (RMS) roughness (Sq) of 2.31 nm. Experimental data and theoretical calculations reveal that the improved CMP performance results from the effective complexation of EDTMPA with Co ions. Furthermore, the adsorption of OHA as a corrosion inhibitor on the Co surface effectively counteracts the corrosion induced by EDTMPA. The development of this novel polishing slurry presents a strategy that harmoniously combines reduced process time with enhanced surface quality, holding the potential to significantly influence the CMP field.

Electrochemical Corrosion Behavior of Thermally Sprayed Nichrome Coating on Duplex Stainless Steel

Abstract Corrosion is a natural phenomenon that gradually deteriorates any material. Mild steel structures are quickly corroded by the sea environment, and thus protective coatings are normally used to prevent corrosion. In this study, atmospheric plasma spray (APS) and detonation gun (DGun) coatings are used to deposit nichrome on duplex stainless steel (DSS 2205). The coated samples were immersed in 3.5 % sodium chloride solution to perform the electrochemical corrosion studies. Microstructural characterization was performed to determine the severity and nature of the corrosion damage. The study shows that DGun coatings are more efficient than APS coatings when combining potentiodynamic polarization curves and electrochemical impedance spectroscopy measurements. DGun-coated samples exhibit a dense microstructure and strong antiparticle adhesion as their primary attributes. This implies that the DGun coating reduces corrosion rates, increases structural longevity, decreases maintenance expenses, and stimulates economic growth.

Electrodeposition and Properties of Composite Ni Coatings Modified with Multilayer Graphene Oxide.

Within the framework of this study, Ni-based composite electrochemical coatings (CECs) modified with multilayer graphene oxide (GO) processed using microwave radiation have been deposited. The process of these coatings' electrodeposition in the potentiodynamic mode has been studied. The structure of Ni-GO and Ni-GO (MW) CECs has been studied using X-ray phase analysis (XPA) and scanning electron microscopy (SEM).It has been shown that the addition of GO into a nickel deposit contributes to the formation of uniform fine-grained coatings. As a result, the microhardness of the Ni-GO (MW) CECs increases by 1.40 times compared to Ni without GO. The corrosion-electrochemical behavior of nickel CECs in 0.5 M H2SO4 solution was researched. It was established that the corrosion rate of the nickel-GO (MW) CEC in 3.5% NaCl decreases by about 1.70 times in contrast to unmodified nickel coatings. This effect is due to the absence of agglomeration of the graphene oxide in the volume of the nickel matrix and the impermeability of GO particles to the corrosive environment.

Electrochemical corrosion behaviour of Zn-Sn-Cu-xNi lead-free solder alloys

Zn-30Sn-2Cu-xNi (x=0, 0.5, 1.0, 1.5, wt.%) lead-free solder alloys were prepared via the casting method. Subsequently, their microstructures and corrosion behaviors in 0.5 mol/L NaCl solution were investigated. The electrochemical behaviour was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques, to evaluate the influence of Ni content on the corrosion performances of the Zn-Sn-Cu alloy. The corrosion mechanism of the Zn-Sn-Cu-Ni alloys was analyzed by observing surface structure evolution during the corrosion process. The results revealed that the addition of 0.5 wt.% Ni improved the corrosion resistance of Zn-30Sn-2Cu alloy due to forming a denser and more homogeneous corrosion layer, which acted as a physical barrier. The phase identification confirmed that the main corrosion products consisted of ZnO, Zn(OH)2, and Zn5(OH)8Cl2·H2O. As the Ni content reached 1.0 and 1.5 wt.%, the corrosion resistance of Zn-30Sn-2Cu alloy declined, which could mainly be attributed to the galvanic corrosion between the (Ni, Cu)5Zn21 intermetallics and Zn-rich phase, accelerating the dissolution of Zn-rich phase. Thus, Zn-30Sn-2Cu-0.5Ni solder alloy showed the best corrosion resistance.

Electrochemical corrosion behaviour of rolled dual phase Mg-8Li-graphene composite

In this research, the effect of interrupted rolling on electrochemical corrosion behaviour of Mg-8Li-xGr composite is investigated. Graphene reinforced composite was developed by using stir casting route and rolled with different reductions in thickness of 50, 75 and 90%. Investigation on potentiodynamic polarization of rolled composite depicts that increase in reduction percentage increases the corrosion rate of the developed composite. Electrochemical impedance studies reveal that composite reduced at 50% thickness exhibits higher charge transfer resistance of 80 Ωcm2. Nyquist plot depicts occurrence of inductance loop that reveals occurrence of oxide layer breakage. Addition of graphene up to 0.4 wt% increase the corrosion resistance and further addition exhibits adverse effect in corrosion behaviour due to the galvanic effects. The occurrence of pitting corrosion is evidenced from corrosion surface morphology.

Electrochemical corrosion performance of copper and uniformly alloyed bronze and brass in 0.1 M NaCl solution

The influence of Al and Zn by 10 wt.% as alloying elements on the electrochemical corrosion behaviour of Cu-based alloy in 0.1 M NaCl solution is examined. Results from both electrochemical impedance spectroscopy method and potentiodynamic techniques indicate that the corrosion occurred at a higher rate for Zn and Al added alloys than pure Cu, where Zn added alloy shows the worst corrosion performance. Copper forms stable a protective layer of Cu2O, and CuO, as a result, has a lower corrosion rate. In case of Al and Zn added alloys, dealloying, as well as dissolution of additional Al2O3 and ZnO are responsible for higher corrosion rates, respectively. The surfaces are investigated by optical and scanning electron microscopy. Phases of different intermetallics within the Cu matrix are identified in the etched optical micrographs of the experimental alloys. The optical images after corrosion depict layers of oxides on the surfaces where the Zn-added alloys are highly affected, followed by Al-added alloys and pure Cu. Increased amounts of internal damage to the surface of the Zn-added alloy are visible in the SEM images. The EDX spectrum not only supports the presence of oxide layers but also claims that Zn-containing particles are dissolved at a greater rate than Al.

Simultaneous improvement of corrosion and wear resistance of Fe–Mn–Al–C lightweight steels: The role of Cr/Mo

Fe–Mn–Al–C lightweight steel has promising applications due to its low density and excellent mechanical properties. This study investigates the influence of Cr/Mo on the electrochemical corrosion and wear behavior of lightweight steel. The results showed that adding Cr/Mo significantly improved the corrosion resistance in NaCl/NaHSO3 solution. This improvement was attributed to the presence of protective Cr/Mo oxides and the reduction of harmful Mn oxides, which increased the compactness and charge transfer resistance of the oxide film. The primary wear types of lightweight steels include abrasive, adhesive, fatigue and oxidative wear. The wear test results showed that adding Cr/Mo improved the wear resistance of lightweight steel, which can be attributed to the increased toughness and hardness gradient.

Investigations of the Wettability and Electrochemical Corrosion Behavior of Nb2O5 Thin Films on a Ti45Nb Alloy

Investigations of the Wettability and Electrochemical Corrosion Behavior of Nb2O5 Thin Films on a Ti45Nb Alloy

SiC nanowires enhanced graphene composite coatings with excellent tribological and anticorrosive properties

The synergistic effect between nanomaterials with different dimensions can enhance wear and corrosion resistance of surface protective coatings. In this work, GO-pva-SiC and RGO-pva-SiC coatings were constructed on stainless steel substrate by combining spraying process and subsequent chemical reduction of hydrazine hydrate. Tribological tests have shown that GO-pva-SiC coating exhibits good lubricating performance under low load and long wear life under high load. After reduction, RGO-pva-SiC coating presents a longer wear resistance life (25,000 cycles) at a lower friction coefficient of 0.11 under 20.0 N. Furthermore, the electrochemical corrosion behavior indicates that the addition of SiC NWs can enhance corrosion resistance of graphene-based coatings. This work provides an efficient way to develop graphene-based composite coatings for practical engineering applications.

Synthesis and Electrochemical Corrosion Behaviour of High Entropy Alloys

Synthesis and Electrochemical Corrosion Behaviour of High Entropy Alloys

Corrosion and cavitation erosion behaviors of laser clad FeNiCoCr high-entropy alloy coatings with different types of TiC reinforcement

By using laser cladding (LC), high entropy alloy coatings (HEACs) with FeNiCoCr as the base material and TiC added directly (D-TiC) and in-situ (I-TiC) were created. The phase composition, microstructure, mechanical characteristics, electrochemical corrosion, and cavitation erosion behavior of HEACs were examined in relation to two TiC addition methods, and a thorough investigation of the effects of mechanical characteristics and corrosion resistance on cavitation erosion behavior was conducted. Large clusters of TiC were visible in the D-TiC HEAC, in contrast to the sparse and scattered distribution of them in the I-TiC HEAC. The average grain size of the composite coating substantially fell from 25.7 μm for FeNiCoCr coating to 11.8 μm for D-TiC coating and 9.4 μm for I-TiC coating when TiC were included in the skeleton. The I-TiC composite coating precipitated by nucleation and growth with the maximum average microhardness of 440 ± 6 HV under the combined action of solid solution strengthening, fine crystal strengthening, and second phase strengthening. In 3.5 wt% NaCl solution, the galvanic corrosion between TiC particles and the FCC matrix significantly weakened the corrosion resistance of the D-TiC HEAC, with the Icorr reaching 3.47 × 10−2 ± 0.8 μA/cm2. The I-TiC HEAC exhibited approximately equal corrosion resistance to FeNiCoCr with an Icorr of merely 5.92 × 10−3 ± 0.3 μA/cm2. Varying cavitation incubation periods (IPs) existed in 316 SS and HEACs at the beginning of the cavitation experiment. The mean depth of erosion rate (MDER) of FeNiCoCr, D-TiC and I-TiC coatings was 0.19 ± 0.09, 0.42 ± 0.04, and 0.15 ± 0.02 μm h−1, respectively, which was only 1/5, 1/2, and 1/6 of that of substrate (0.90 ± 0.13 μm h−1). The cavitation surface of 316 SS was full of craters and cracks without any original surface. Meanwhile, due to the weak interfacial bonding strength between TiC/HEA, the cavitation erosion morphologies of D-TiC HEAC contained spallation of large TiC particles. Attributed to its ideal mechanical and corrosion resistance, the I-TiC composite coating demonstrated the best resistance to cavitation erosion.

Effect of oxide layer on the electrochemical corrosion behavior of a Ni-based superalloy in 3.5 wt% NaCl

The recycle technology of superalloy is a research hotspot and difficulty in the filed of superalloy. Recovery of superalloy bulk material is a major focus. Purification smelting after surface impurity removal is an application trend of superalloy regeneration technology. During the use and processing of superalloy, the surface will form a dense oxide layer. The oxide layer of superalloy scrap is difficult to remove by traditional mechanical method. However, the oxide layer on the superalloy surface can be efficiently removed by electrochemical dissolution. Based on the background above, we investigated the electrochemical corrosion behavior of GH4738 superalloy which oxidized for different time in 3.5 wt% NaCl. The effect of oxide layer on the electrochemical corrosion behavior of GH4738 was studied by potentiodynamic polarization and electrochemical impendence spectroscopy(EIS). The morphology and phase composition of the alloy were analyzed by scanning electron microscope (SEM), electron probe X-ray Micro-Analyzer (EPMA) and X-ray diffraction (XRD). The results indicated that the dense oxide film not only has a protective effect on the oxidation corrosion of the alloy, but also has a protective effect on the electrochemical corrosion of the alloy. The oxide layer impedes the electrochemical dissolution of the alloy.