Cathodic Corrosion Research Articles

Cathodic corrosion induced selective nano-crystallization of Nickel oxo/hydroxo complex on (NiFeCr)SiB amorphous ribbon for alkaline oxygen evolution reaction and methanol oxidation reaction

The study focuses on the development and optimization of (Ni87Fe4Cr9)78Si8B14 amorphous ribbons as self-supported electro-catalysts for oxygen evolution reaction (OER) and methanol oxidation reaction (MOR). Electro-catalytically active nano α-Ni(OH)2 phase (5–10nm) was generated in the amorphous ribbon surface through potentiostatic cathodic corrosion for different time intervals (0–120 min). The X-ray diffraction and scanning electron microscopy results shows the favourable occurrence of dense nanocrystallization of α-Ni(OH)2 between 45 and 90 min of corrosion time. For OER in 1 M KOH, the 60-min surface modified ribbon exhibits an overpotential of 295 mV at 10 mA/cm2 current density and tafel slope of 51 mV dec−1. In case of MOR in 1 M KOH +1 M MeOH, the 90-min corroded ribbon shows lowest potential of 1.38 V vs RHE, at 10 mA/cm2 and tafel slope of 34 mV dec−1. In addition to superior electro-catalytic activity, the optimal surface-modified ribbons show superior long-term stability for OER and MOR studies, indicating its potential application in hydrogen generation and direct methanol fuel cell.

Electrochemical activation of Pt electrode for efficient and stable anion exchange membrane ammonia electrolyzer

Replacing the oxygen evolution reaction in water electrolysis with ammonia oxidation reaction enables low voltage hydrogen production. Pt is a promising catalyst for the ammonia oxidation reaction due to its superior dehydrogenation and low affinity for *N, but Nads poisoning deactivates the Pt surface. This study proposes a method to improve ammonia oxidation performance and stability through electrochemical activation, introducing cathodic corrosion and recovery conditions. The half-cell results showed a peak current density of 74.2 mA cm−2 and retention ratio of 17 %. Adjusting the lower and upper cell voltage in a membrane electrode assembly based single cell optimized surface cleaning and inhibits further poisoning by O/OHads above 0.75 Vcell. Furthermore, incorporation of recovery conditions can enhance the stability of poisoned electrode compared to that in chronoamperometry test. The results of pulsed ammonia electrolysis tests incorporating recovery conditions suggested a novel approach to practical hydrogen production by stabilizing catalysts with a 83 % Faradaic efficiency at 0.1 A cm−2

Influence of Carboxymethyl Chitosan and Sodium Humate Composite Corrosion Inhibitor on the Corrosion Resistance of EH40 Steel in Seawater.

In this study, corrosion weight loss experiments were conducted to explore the corrosion-inhibiting properties of a composite inhibitor consisting of carboxymethyl chitosan (CMCS) and sodium humate (SH) at varying concentrations on EH40 steel in seawater. An investigation was conducted into the electrochemical behavior of EH40 steel in seawater and the mechanism of composite inhibitor consisting of carboxymethyl chitosan (CMCS) and sodium humate (SH) at varying concentrations on EH40 steel in seawater through an electrochemical test. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy and energy-dispersion spectroscopy (SEM-EDS), Fourier transform infrared absorption spectroscopy (FTIR), and contact angle measurements were performed to confirm the mechanism of CMCS and SH as well as their composite corrosion inhibitors at the interface between seawater and EH40 steel. Furthermore, density functional theory (DFT) calculation supports the experimental findings. The results show that CMCS, SH, and their composite inhibitor are a mixed type of corrosion inhibitor that mainly inhibits cathodic reactions and corrosion through the active site blocking mechanisms. Their corrosion inhibition effect increases with the increase of mass concentration, and the composite inhibitor performs better in corrosion inhibition and scale inhibition than the individual inhibitor. When the CMCS mass concentration reaches 100 mg/L and the SH mass concentration reaches 50 mg/L, the corrosion inhibition rate is 74.65%, the corrosion potential shifts by about 47.39 mV, the Rp value increases from 358.6 to 1102.4 Ω·cm2, and the Ydl value decreases from 177.31 Sn Ω-1cm-2 × 10-6 to 92.672 Sn Ω-1cm-2 × 10-6. CMCS and SH are adsorbed onto the surface of EH40 steel, forming a protective film through the complexation of carboxyl, amino, and other functional groups to inhibit corrosion and prevent the further formation of scale. In addition, synergistic coadsorption occurs between CMCS and SH, and the composite corrosion inhibitor exerts a better effect than the individual corrosion inhibitor.

Corrosion protection of mild steel via cerium nitrate loaded acrylic-vinyl polysilazane based hybrid coatings

This study presents an efficient anticorrosive coating based on an organic-inorganic hybrid polymer composed of methyl methacrylate, styrene, tert-butyl acrylate, and vinyl polysilazane. The synthesized resin exhibits excellent thermal resistance and stability, as confirmed by thermogravimetric analysis (TGA). Additionally, leveraging the resin's highly alkaline nature, cerium oxide (CeO2) nanoparticles were doped in situ within the polymer matrix. The hybrid resins were subsequently applied to mild steel panels using a dip-coating technique. The resulting coatings are transparent, flexible, thin, pore-free, and possess low surface roughness (<2.62 nm), along with good thermal stability (>350 °C). Their remarkable anticorrosive performance and durability are attributed to forming a highly crosslinked acrylic-polysilazane network, combined with a cerium oxide protective barrier layer that adheres to the substrate. Furthermore, the cerium ions suppress both cathodic and anodic corrosion reactions, enhancing the corrosion resistance. Notably, the coating system containing 2 wt% cerium achieved a high impedance value of 106 Ω cm2, corresponding to a corrosion rate of 0.112 × 10−5 mm/year. This study demonstrates that these acrylic-vinyl polysilazane coatings, incorporating ceria as a corrosion inhibitor, offer a promising alternative to conventional protection systems.

Micro-galvanic corrosion behaviour of Mg−(7,9)Al−1Fe−xNd alloys

The localized micro-galvanic corrosion process and the kinetic information of Mg−(7,9)Al−1Fe−xNd alloys were investigated by in situ observation under electrochemical control and in situ atomic force microscopy (AFM) in an electrolyte environment. The results revealed that the formation of the Nd-rich phase in alloys resulted in a decrease in the Volta potential difference from ~400 mV (AlFe3/α-Mg) to ~220 mV (Nd-rich/α-Mg), reducing the corrosion products around the cathodic phase and corrosion current density of the microscale area. The addition of Nd significantly improved the corrosion resistance, mainly due to the suppression of the micro-galvanic corrosion between the second phases and substrate. Finally, the corrosion mechanism of Mg−(7,9)Al−1Fe−xNd alloys was discussed based on in situ observations and electrochemical results.

Modeling Stochastic Kinetics of Cathodic Cu Surface Corrosion and Ionic Interaction in Nanoscopic Water Pools

Cathodic Cu corrosion has been reported to occur in both the presence and absence of carbon dioxide in aqueous electrolytes and while the mechanism is not understood well it implies carbide-, hydride- and hydroxide-formation mediated pathways. Corrosion leads to roughening, which creates local pockets of electrolyte that are somewhat disconnected from the bulk. In this talk, we describe a combination of theoretical studies to identify reaction pathways, and kinetics modeling of them to obtain a working description of corrosion in water. Corrosion at metal surfaces is both influenced by and influences the formation of nanoscopic aqueous pools by trapping electrolyte solution in microscopic pockets. Such electrolyte nano-pools exhibit non-bulk behavior, and the lifetime of locally trapped ions can be significantly different than in the bulk. This can potentially have an effect on the chemistry in the local microenvironment. Stochastic reaction-diffusion models can be used to model kinetics of electrochemical processes at length and time scales relevant to laboratory experiments, allowing a direct comparison of transient observable quantities to time-resolved experimental data. Atomistic simulations employ methods of electronic structure theory (such as density functional theory (DFT)) and molecular dynamics (both classical and ab initio) to describe a detailed picture of the (electro-)chemistry at microscopic time and length scales. Scaling up these methods to macroscopic levels is not trivial but required for direct comparison to experiment. By using Gibbs free energies obtained from atomistic simulations it is possible to calculate rate constants for individual elementary steps in reaction schemes describing kinetics of relevant processes. We use Kinetiscope to implement stochastic kinetics models of two reaction schemes describing: 1. cathodic Cu surface corrosion through formation of copper hydroxides, through which we aim to describe essential steps in the cathodic corrosion mechanism of metal surfaces; 2. interactions between bicarbonate and hydronium ions, both present in the bicarbonate salt buffers used routinely in electrochemical reduction at copper surfaces, in a nanoscopic water droplet to understand time-dependent changes in the local concentrations of electrolytes trapped at or near metal surfaces. Figure 1

Mitigating the HER-Promoted Corrosion of Lead Cathodes during Electrosynthesis

The hydrogen evolution reaction (HER) is a significant side reaction that lowers the faradaic efficiency of electrochemical reductions in aqueous electrolytes. HER has also been identified as a primary contributor to cathodic corrosion for metals like lead, tin, and mercury—commonly employed as cathodes in electrosynthesis. Consequently, the suppression of HER is of paramount importance, not only for enhancing product faradaic efficiencies but also for mitigating corrosion and extending the lifetime of metal cathodes.In the present study, we demonstrate the suppression of HER over lead electrodes in an acidic electrolyte through the addition of the quaternary ammonium salt N,N,N,N’,N’,N’-hexamethyl-1,12-dodecanediammonium methyl sulfate (H12MS). The quaternary ammonium ions electrostatically interact with the surface of the negatively charged lead electrode, creating a cationic layer that protects the cathode’s surface by repelling hydroniums, thereby suppressing HER. The amount of evolved hydrogen was estimated by conducting chronoamperometry (CA) experiments at a potential of -1.8 V vs. Ag/AgCl (after the onset of HER) for 1 hour in a 0.1 M H2SO4 solution (pH 1). It is observed that the hydrogen produced dropped from ~1.62 mmol/cm2 to ~0.26 mmol/cm2 in the presence of 1 mM H12MS. Further, we notice that the current increased monotonically with time for the blank lead electrode during CA (-43.76 to -114.57 mA/cm2), indicating an increase in the exposed surface area due to corrosion. In contrast, the current remained almost constant (-13.2 to -13.8 mA/cm2) in the presence of 1 mM of H12MS, indicating that cathodic corrosion is mitigated. This mitigation in cathodic corrosion is further supported by the scanning electron microscopy images acquired after 1 hour of vigorous HER process. Without H12MS, the lead coupon exhibited significant surface disintegration, indicative of cathodic corrosion. Conversely, in the presence of 1mM H12MS, the surface of the lead coupon remained intact after HER, affirming the successful mitigation of the corrosion process. Our findings for electrochemical hydrogenation will be extended to electrocatalytic transformations, for example, to favor electro-hydrogenation over HER on PGM catalysts.

Leaded Bronze Foams As Innovative Electrodes for Organic Electrosynthesis

The electrification of organic synthesis represents an outstanding green alternative to prepare valuable and fine chemicals. However, the design of electrode materials for organic electrosynthesis remains as an open field to investigate. Motivated by the superior performance of leaded bronzes as electrodes for reductive transformations,[1, 2, 3] we have developed highly porous binary and ternary leaded metal foams through the dynamic hydrogen bubble template method [4] and tested them as cathodes in the electro-organic synthesis of 2,6-dichlorobenzonitrile from 2,6-dichlorobenzaldoxime.[5]The electrocatalytic performance of the novel leaded foams was compared to the one of the planar CuSn7Pb15 leaded bronze. The novel porous leaded foams outperformed the CuSn7Pb15 electrodes in terms of chemical yield and energy efficiency. Furthermore, due to their highly crystalline surface, these materials are mechanically more stable and less prone to cathodic corrosion than flat Pb and CuSn7Pb15 electrodes.

Optimizing the Atomic Structure of Ruthenium Deposited on Pt/C Cathode Catalysts to Enhance Durability of Automotive Fuel Cell

Proton exchange membrane fuel cells (PEMFCs) for automotive applications suffer from cathode corrosion problems due to the sudden potential jump caused by unintended air leakage into the anodic flow field during start-up and shut-down (SU/SD) events. Here, we report a solution to the instantaneous potential jump issue during SU/SD events by imparting oxygen evolution reaction (OER) activity to the PEMFC cathodic catalyst to preferentially promote OER and suppress the unwanted carbon oxidation reaction at the cathode. In the newly developed Ru-on-Pt/C electrocatalyst, the small particle size of sputtered Ru and the Ru–Pt interaction significantly improve activity–stability for OER and prevent corrosion in cathode by preemptively consuming electrons related to the potential jump. Membrane electrode assemblies constructed using Ru-on-Pt/C showed an extraordinary (98 %) performance retention after repeating the SU/SD protocol test 100 times, demonstrating unprecedented state-of-the-art durability.

Exploration of UV-induced geometrical isomer-enriched Helichrysum kraussii extract as a corrosion inhibitor for Al(111) surface in 1.0 M hydrochloric acid: An experimental and theoretical study

This study evaluated UV-radiated Helichrysum kraussii (H. kraussii) extract for its corrosion inhibition on aluminium in 1.0 M HCl. To achieve this, techniques such as Liquid chromatography-mass spectrometry (LC-MS), Fourier transform infrared spectroscopy (FTIR), Gravimetric analysis, electrochemical analysis looking at electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), contact angle and computational studies were used. The results obtained from these techniques made it possible to conclude the performance of UV-radiated H. kraussii as a corrosion inhibitor for aluminium metal. LC-MS and FTIR proved that the exposure of extract to UV radiation caused a change in the composition of extract metabolites, demonstrated by the increase in the number of peaks in the chromatogram and the shift in the FTIR spectrum. Weight loss technique showed that the extract inhibited the corrosion of aluminium with the maximum percentage inhibition of 84.6948 % at the concentration of 1500 ppm at 30 °C. The adsorption of the inhibitor molecules on the metal surface was found to obey the Langmuir adsorption isotherm, and the activation energy values proved that the adsorption mechanism was through physisorption. Nyquist plots semi-circles were found to increase with an increase in the extract concentration, showing an increase in the inhibition efficiency. Tafel's plot showed that both anodic and cathodic corrosion were inhibited. The DFT/PBE/GGA/DNP computational investigation obtained binding energies of the inhibitors on the aluminium surface that suggest that the Al···FA interaction happens through physical adsorption.

Improving Scalability of copper recovery in saline microbial fuel cells with microtubular polypyrrole-based cathodic electrocatalysts

Microbial fuel cells (MFC) are emerging energy-efficient systems for copper (Cu) electrowinning from waste streams by coupling it with anodic oxidation of organics in wastewater. However, there is a lack of research examining scalable electrocatalysts for Cu electrowinning at low cathodic overpotentials in highly saline catholytes often found in e-waste leachates. The challenge of developing resilient anodic biofilms that withstand the antagonistic effects of ions migrating from catholytes in saline MFC also needs to be addressed. In this study, polypyrrole (PPy) cathodic electrocatalysts were developed and coupled with a robust halophilic anodic biofilm in MFC to improve the kinetics of Cu electrowinning from acidic chloride-based catholytes. Electrochemical characterisation of these cathodes revealed shuttling of electrons by redox-active PPy via the formation of intermediate Cu+-complexes as an energy-efficient pathway for producing metallic Cu. High power densities ranging from 0.63 ± 0.17 to 0.73 ± 0.05 W m−2 were achieved with undoped-PPy and phytic acid doped-PPy cathodes with simultaneous recovery of ∼97% Cu. These electrocatalysts also exhibited low charge transfer resistance (3–8 mΩ m2) that met the requisites for scalable cathodes in MFC. However, a decrease in the efficiency of PPy cathodes was observed over 5 d due to competing reactions at their interfaces, including re-oxidation of deposited Cu and cathodic corrosion, with further studies suggested to enhance their corrosion resistance. Nonetheless, integrating PPy electrocatalysts for Cu electrowinning in saline MFC has advanced its outlooks as an energy-efficient downstream process for urban mining of Cu from e-waste.

The impact of oxygen availability on steel corrosion considering the self-balance between anodic and cathodic corrosion cells

An advanced model is developed to elucidate relationship between availability of oxygen and active corrosion, considering the equilibrium between gaseous and dissolved oxygen, as well as the equilibrium of oxygen diffusion and consumption. This research notably incorporates self-regulation mechanisms of cathodes and anodes in both macrocell and microcell corrosion. Accelerated corrosion experiments were performed under simulated marine environment, monitoring variations in corrosive medium concentration and electrochemical corrosion processes. Results indicate significant reduction in oxygen concentration following the activation of rebar. Potential inaccuracies in predicting corrosion rate arise from the adoption of a static cathodic to anodic area ratio was highlighted.

Electrochemical activation of peroxymonosulfate facilitated by a stainless-steel scrubber cathode: Transition from non-radical to radical pathway mediated by iron leaching

This study investigated the feasibility and underlying mechanisms of peroxymonosulfate (PMS) activation by a stainless-steel scrubber (SSS) cathode. Experimental findings revealed that the system could achieve 100 % degradation of sulfamethoxazole (SMX) in 30 min at initial pH value ranging from 3 to 9. The activation mechanism was observed to occur in two distinct stages. The first stage was characterized by a non-radical 1O2 dominance (0–6 min), where the activation of PMS and O2 was primarily facilitated through direct electron transfer at the cathode surface. Subsequently, the second stage transitioned to a radical dominance (6–18 min), with SO4− playing a pivotal role. This was attributed to the release of Fe2+ ions resulting from cathodic corrosion, which induced both homogeneous and heterogeneous Fenton-like reactions. The PMS/SSS cathode system exhibited anti-interference against most water matrices, except for HCO3−. Notably, the system demonstrated exceptional performance in the degradation of pollutants within phosphate wastewater samples, suggesting its potential for application in such contexts. In addition, the electrical energy was calculated to be 0.025 kWh·m−3 at a current of 0.01 A and a voltage of approximately 2.0 V, providing significant economic benefits.

Corrosion inhibition by amino acid functionalized chitosan derivative at Q235 steel/ H2SO4 solution interface: Experimental and surface investigations

The present work describes the chitosan derivative development using amino acid (Vanilline) (CASB). The developed compound was used as Q235 steel corrosion inhibitor in 1 M H2SO4 using weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). The EIS results disclosed that CASB inhibits corrosion via charge transfer process. The PDP data indicated that CASB suppresses both the cathodic and anodic corrosion process. The maximum inhibition efficiency of CASB (100 mg/L) and KI+75 mg/L (CASB) are 95.8 % and 97.9 % respectively. The adsorption of CASB over the Q235 steel surface was confirmed using X-ray photoelectron spectroscopy (XPS). Morphological changes on the steel surface were monitored by scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The Langmuir adsorption isotherm provided best fitting of experimental data. Density functional theory (DFT) and Molecular dynamic simulation (MD) suggests that neutral forms of CASB have more adsorption ability than neutral forms.

Electrochemical, Structural and Thermodynamic Investigations of Methanolic Parsley Extract as a Green Corrosion Inhibitor for C37 Steel in HCl

Phytochemical-rich natural extracts have recently attracted intense attention as green corrosion inhibitors and costly benign coating components for the protection of metallic structures of immense commercial importance. Herein, various methods were applied to assess the corrosion protection efficiency of a methanolic extract of parsley (Petroselinum crispum) (PCE) on carbon steel C37 in 1 M HCl. Initially, the chemical profile of PCE was analyzed using gas chromatography/mass spectrometry (GC/MS), and myristicin and apiol were identified as the main components. The results from the weight loss, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques revealed a substantial reduction in the corrosion rate upon the use of PCE, with a maximum inhibition efficiency of 92% at 1 g L−1 PCE. To optimize the performance, the corrosion behavior was investigated over a temperature range of 303–333 K and for concentrations of 0.1–1 g L−1. The inhibition effectiveness increased at higher concentrations of PCE, whilst it decreased when the temperature was elevated. The query suggests that the adsorption process involves both physical and chemical mechanisms. The adsorption of PCE onto C37 was well described by the Langmuir adsorption isotherm. The data were used to determine the activation energy and thermodynamic parameters. The PCE coating acted as a mixed-type inhibitor, hampering both cathodic and anodic corrosion reactions. SEM further confirmed the formation of a protective coating film on the steel surface when exposed to PCE. UV-Vis and XRD were implemented to understand the inhibition mechanism and formed products at the microscopic and spectroscopic levels. Hence, the green PCE inhibitor may potentially be applied in corrosion mitigation due to its high corrosion protection efficacy and its environmentally benign nature.

Ionic Liquids as Cathode Additives for High Voltage Lithium Batteries

AbstractTwo oxalatoborate ionic liquids (ILs), which are commonly utilized as electrolyte additives that form a protective layer on the cathode surface, are investigated for the first time as electrode additives. Cathodes based on LiNi0.5Mn1.5O4 (LNMO) containing 3 wt % ILs, i. e., “IL‐enriched cathodes”, exhibit capacity values above 120 mAh/g with high Coulombic efficiencies throughout cycling over 200 times. A cathode without ILs also exhibits a capacity of 119 mAh/g but its Coulombic efficiency becomes low and unstable after 109 cycles. In addition, when 0.3 M ILs are added to conventional carbonate‐based electrolytes, the battery cycle life improves but there is a reduction in the capacity probably due to low ionic conductivity of the electrolyte mixtures. Post‐mortem analyses of electrodes retrieved from cycled cells highlight less electrolyte decomposition and less cathode corrosion, enabled by using the IL as the additive in LNMO, which are confirmed by a particle shape with smooth surface identical to the fresh cathode. The study demonstrates that oxalatoborate ILs can be used as the electrode additive, and this provides a new concept for cathode formulations for high performance batteries with a small amount of ILs.

Mitigating Cathode Corrosion in Aluminum Reduction Cells Using a VOF-Electric Model

Mitigating Cathode Corrosion in Aluminum Reduction Cells Using a VOF-Electric Model

Effect of Alkali Metal Cations and Trace Metal Impurities on Cathodic Corrosion of Gold Electrode Surfaces

AbstractIn this work, we comprehensively studied the cathodic corrosion of Au electrodes as a function of the identity of alkali metal hydroxides at different concentrations and various negative potentials. We reveal that the ratio of free water and water bound in hydration shells controls the overall cathodic corrosion behavior, alongside the specific adsorption of alkali metal cations. Moreover, we highlight the crucial role of electrolyte cleanliness, particularly regarding the presence of trace metal impurities. Interestingly, the presence of trace amounts of nickel and iron in as‐received CsOH suppresses cathodic corrosion by their deposition onto Au surfaces. In contrast, after purification the polarization of Au surfaces in 10 M CsOH leads to the formation of nanoporous surfaces with high electrochemically active surface area, in which the degree of porosity can be tuned by varying the polarization time at −1.6 V vs. RHE.

Quasi-Solid-State Electrolyte Induced by Metallic MoS2 for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are a promising high-energy-density technology for next-generation energy storage but suffer from an inadequate lifespan. The poor cycle life of Li-S batteries stems from their commonly adopted catholyte-mediated operating mechanism, where the shuttling of dissolved polysulfides results in active material loss on the sulfur cathode and surface corrosion on the lithium anode. Here, we report in situ formation of a quasi-solid-state electrolyte (QSSE) on the metallic 1T phase molybdenum disulfide (MoS2) host that extends the lifetime of Li-S batteries. We find that the metallic 1T phase MoS2 host is able to initiate the ring-opening polymerization of 1,3-dioxolane (DOL), forming an integrated QSSE inside batteries. Nuclear magnetic resonance analysis reveals that the QSSE consists of ∼13% liquid DOL in a solid polymer matrix. The QSSE efficiently mediates sulfur redox reactions through dissolution-conversion chemistry while simultaneously suppressing polysulfide shuttling. Therefore, while ensuring high sulfur utilization, it avoids degradation of both electrodes, as well as the concomitant electrolyte consumption, leading to enhanced cycling stability. Under a practical lean electrolyte condition (electrolyte-to-sulfur ratio = 2 μL mg-1), Li-S pouch cell batteries with the QSSE demonstrate a capacity retention of 80.7% after 200 cycles, much superior to conventional liquid electrolyte cells that fail within 70 cycles. The QSSE also enables Li-S pouch cell batteries to operate across a wider temperature range (5 to 45 °C), together with improved safety under mechanical damage.

Anodic Dissolution Characteristics of GH4169 Alloy in NaNO3 Solutions by Roll-Print Mask Electrochemical Machining Using the Linear Cathode.

GH4169 alloy/Inconel 718 is extensively utilized in aerospace manufacturing due to its excellent high temperature mechanical properties. Micro-structuring on the workpiece surface can enhance its properties further. Through-mask electrochemical micromachining (TMEMM) is a promising and potential processing method for nickel-based superalloys. It can effectively solve the problem that traditional processing methods are difficult to achieve large-scale, high-precision and efficiency processing of surface micro-structure. This study explores the feasibility of electrochemical machining (ECM) for GH4169 using roll-print mask electrochemical machining with a linear cathode. Electrochemical dissolution characteristics of GH4169 alloy were analyzed in various electrolyte solutions and concentrations. Key parameters including cathode sizes, applied voltage and corrosion time were studied in the roll-print mask electrochemical machining. A qualitative model for micro-pit formation on GH4169 was established. Optimal parameters were determined through experiments: 300 μm mask hole and cathode size, 10 wt% NaNO3 electrolyte, 12 V voltage, 6 s corrosion time. The results demonstrate that the micro-pits with a diameter of 402.3 μm, depth of 92.8 μm and etch factor (EF) of 1.81 show an excellent profile and localization.