Inherent Defects Research Articles

Cashew phenol modified lignosulfonate strategy for the preparation of high-performance dye dispersants.

Lignin-based dye dispersants (LDD), as one of the most common lignin resource end-application product, is difficult to meet the rapidly developing needs of modern fiber dyeing due to their inherent structural defects. The efficient upgrading and modification of LDD is of great significance to the value-added application of lignin resources and the expansion of LDD sinking market. In this study, using industrial kraft lignin as raw material, cashew phenol was introduced into lignosulfonate in the form of CC bonds by ingenious utilizing the structural characteristics of lignin disordered condensation. Aromatic ring in cashew phenol could provide sufficient sulfonic acid group grafting sites, while C15 fatty chain could enhance steric hindrance effect. In the dispersibility test, the dispersing power showed 99.09 %, and the low/high temperature dispersion (LTD/HTD) were 5 s/4 and 6 s/4, respectively, higher than the dispersibility level of LDD in the market, has great commercial value and industrial potential. Combined with FTIR, 1H NMR, GPC and ICP, the structural properties of lignin were analyzed in detail, and the degree of sulfonation-condensation was balanced-optimized. The CC bond condensation process between cashew phenol and lignin was revealed, and the mechanism of action on dye particles was elucidated.

Sb-anchoring single-crystal engineering enables ultra-high-Ni layered oxides with high-voltage tolerance and long-cycle stability

Ni-rich layered oxides are promising cathodes for Li-ion batteries, but the inherent structural defects result in severe surface/bulk degradation during long cycling, especially at high cutoff voltage. Herein we propose a Sb-anchoring single-crystalline engineering to enhance the microstructural and electrochemical stability of ultra-high-Ni layered oxides, where the surface-enriched Sb doping inhibits Li-Ni mixing, suppressing the undesired layered to mixed/rock-salt phase transformation; the bulk-doped Sb rivets into Ni sites, reinforcing the bulk phase stability; the single-crystal endows enhanced crack resistance and reduced surface area, preventing surface parasitic reactions and the subsequent proliferation of cathode electrolyte interfaces. In-situ XRD reveals an essential correlation between cycle stability and phase reversibility, whereas Sb doping into both surface and bulk structures showcases a continuous anchoring effect, largely enhancing the phase transformation reversibility. DFT calculations prove a high oxidation tolerance, as Ni2+ diffusion barrier is higher than the pure cathode. A representative Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2 cathode exhibits a high-voltage up to 4.6V, and a Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2//graphite full-cell demonstrates an ultra-high capacity retention of 93.4% after 1000 cycles at 1C in 3.0−4.2V. This simple and efficient cathode engineering will promote the promising application of Ni-rich layered oxides in high-energy Li-ion batteries.

Hollow and heterojunction-structured Janus nanomotors for pyroelectrodynamic and nanozyme-catalyzed tumor therapy

Pyroelectrodynamic therapy (PEDT) has emerged as an attractive therapeutic modality for tumors, but is dramatically discounted by inherent defects of wide band gap, fast electron − hole recombination and low photothermal utilization. Herein, hollow-structured Janus nanoparticles (NPs) are developed to improve tumor accumulation and PEDT generation of reactive oxidative species (ROS) for antitumor treatment. Hollow barium titanate (hBT) NPs were prepared by the template and hydrothermal method for in situ deposition of CuS nanodots and then partially coated with polydopamine (PDA) caps to obtain hBT-CuS@PDA. Finite element analysis reveals that the unique thin shell of hBT benefits transportation of pyroelectrically generated charge carriers through shortening diffusion distance to the interface. The CuS deposition forms heterojunctions with hBT to accelerate electron − hole separation and leads to a larger pyroelectric current. The hollow structure facilitates light absorption and conversion, and the photothermal effect of the half-coated PDA caps generates asymmetric temperature gradient to drive NP locomotion across biological barriers. The in situ generated pyroelectric field selectively affects membrane potential and fluidity of tumor cells to enhance the specific NP internalization. The pyroelectric effect enhances the peroxidase-like activity of CuS nanodots to generate toxic ·OH and the glutathione peroxidase-like activity to inhibit glutathione consumption of ROS. The integration of photothermal, pyroelectric, nanozyme catalysis and self-protrusion effects promotes NP accumulation and penetration throughout tumors to exhibit therapeutic effect at a mild-temperature, reducing the possible high-temperature ablation of normal tissues. The hollow and heterjunction structure generates abundant intracellular ROS and efficient diffusion in tumor tissues to inhibit tumor growth and extend animal survival, offering a safe and effective PEDT strategy.

On Transforming Reinforcement Learning With Transformers: The Development Trajectory.

Transformers, originally devised for natural language processing (NLP), have also produced significant successes in computer vision (CV). Due to their strong expression power, researchers are investigating ways to deploy transformers for reinforcement learning (RL), and transformer-based models have manifested their potential in representative RL benchmarks. In this paper, we collect and dissect recent advances concerning the transformation of RL with transformers (transformer-based RL (TRL)) to explore the development trajectory and future trends of this field. We group the existing developments into two categories: architecture enhancements and trajectory optimizations, and examine the main applications of TRL in robotic manipulation, text-based games (TBGs), navigation, and autonomous driving. Architecture enhancement methods consider how to apply the powerful transformer structure to RL problems under the traditional RL framework, facilitating more precise modeling of agents and environments compared to traditional deep RL techniques. However, these methods are still limited by the inherent defects of traditional RL algorithms, such as bootstrapping and the "deadly triad". Trajectory optimization methods treat RL problems as sequence modeling problems and train a joint state-action model over entire trajectories under the behavior cloning framework; such approaches are able to extract policies from static datasets and fully use the long-sequence modeling capabilities of transformers. Given these advancements, the limitations and challenges in TRL are reviewed and proposals regarding future research directions are discussed. We hope that this survey can provide a detailed introduction to TRL and motivate future research in this rapidly developing field.

Enhanced corrosion resistance of a novel periodic multilayered Si/(Si, N)-DLC coating against simulated coal mine water

In this study, a novel periodic multilayered DLC coating, which was composed of a Si interlayer and a Si/N co-incorporated DLC layer (Si/(Si, N)-DLC) per period, was deposited; the corrosion behavior under the neutral, acidic, or alkaline coal mine water environment and its periodic number dependence, especially the fundamental corrosion mechanism, were systemically explored. Results suggest that compare to the substrate, the introduction of multilayered Si/(Si, N)-DLC coating presents a dramatic enhancement in the corrosion resistance under coal mine water environment. However, with increasing the periodic number, the corrosion resistance of the multilayered coating strongly depends on the working environment, which exhibits an enhancement in neutral and alkaline environments while a degeneration in acidic environment. This is attributed to not only the prolongation of the corrosion path caused by the multilayered structure but also the formation of an insulating silicon oxide layer in neutral and alkaline environments. However, in acidic environments, the strong permeability of H+ with the smallest ionic radius easily infiltrates the inherent defects of the coating. This not only weakens the protective properties of the multilayer structure but also leads to hydrogen-induced cracking, ultimately diminishing corrosion resistance. These findings theoretically guide the development of the DLC coatings with excellent corrosion resistance for coal mine applications.

Thermal runaway properties of power cells under tunnel scenarios: Impact of heating patterns and heating powers

Due to the rapid increase in the number of electric vehicles and tunnels in cities, combining the inherent safety defect of power cells, the thermal runaway risk of power cells in tunnels requires significant attention. Herein, an experimental exploration is carried out to unveil the thermal runaway properties of power cells at tunnel scenarios, whereby the impact of heating patterns (electric oven and plate) and heating powers is involved as well. Under the effect of various heating patterns, cells show quite different thermal runaway properties inside a tunnel. In the oven case, the cell is uniformly heated, leading to two instances of smoke/gas release, followed by ejection fire and stable combustion. Whereas, the cell under the plate pattern illustrates smoke/gas releasing only once, with no combustion occurring due to the relatively low surrounding temperature. In addition, the cell affected by a plate experiences a process of thermal runaway propagation, i.e., the left part of the cell encounters thermal runaway first and then propagates to the right part, with the severity of the thermal runaway increasing over time. The cell heated by an oven illustrates worse thermal hazards with a more dramatic temperature rise and heat release, though the associated smoke hazard is relatively mild. The thermal conductivity of the cells is calculated to be approximately 3800 W/(m·K). The power of electric ovens and plates shows little impact on the heat release, mass loss, and smoke release of cells during thermal runaway. Finally, the dimensionless temperature rise at specific positions along the tunnel ceiling exhibits an exponential reduction as the dimensionless position increases during thermal runaway.

Combination Using Magnetic Iron Oxide Nanoparticles and Magnetic Field for Cancer Therapy.

Iron oxide nanoparticles (MNPs) demonstrate notable benefits in magnetic induction, attributed to their distinctive physical and chemical attributes. Emerging cancer treatment utilizing magnetic fields have also gathered increasing attention in the biomedical field. However, the defects of difficult dispersion and poor biocompatibility of MNPs seriously hinder their application. In order to overcome its inherent defects and maximize the therapeutic potential of MNPs, various functionalized MNPs have been developed, and numerous combined treatment methods based on MNPs have been widely studied. In this review, we compare and analyze the common nanoparticles based on MNPs with different sizes, shapes, and functional modifications. Additionally, we introduced the therapeutic mechanisms of the strategies, such as magnetically controlled targeting, magnetic hyperthermia, and magneto-mechanical effect, which based on the unique magnetic induction capabilities of MNPs. Finally, main challenges of MNPs as smart nanomaterials were also discussed. This review seeks to offer a thorough overview of MNPs in biomedicine and a new sight for their application in tumor treatment.

Hybrid Strategies for Enhancing the Multifunctionality of Smart Dynamic Molecular Crystal Materials.

Dynamic molecular crystals are an emerging class of smart engineering materials that possess unique ability to convert external energy into mechanical motion. Moreover, they have being considered as strong candidates for dynamic elements in applications such as flexible electronic devices, artificial muscles, sensors, and soft robots. However, the inherent defects of molecular crystals like brittleness, short-life and fatigue, have significantly impeded their practical applications. Inspired by the concept of "the whole is greater than the sum of its parts" in the field of biology, building stimuli-response composites materials can be regarded as one of the ways to break through the current limitations of dynamic molecular crystals. Moreover, the hybrid materials can exhibit new functionalities that cannot be achieved by a single object. In this review, the focus was placed on the analysis and discussion of various hybrid strategies and options, as well as the functionalities of hybrid dynamic molecular crystal materials and the important practical applications of composite materials, with the introduction of photomechanical molecular crystals and flexible molecular crystals as a starting point.Moreover, the efficiency, limitations, and advantages of different hybrid methods were compared and discussed.

Démence Précoce: Historical Conceptualization of the Concept

Schizophrenia, like many mental disorders, was historically viewed as madness or demonic possession until the 18th century when psychiatry began to emerge as a scientific discipline. French psychiatrist Bénédict Morel played a pivotal role in this transformation by coining the term "<i>démence précoce</i>." He used this term to describe a set of clinical features observed in schizophrenia, suggesting that it was due to an inherent biological defect that progressively worsened through successive generations. German psychiatrist Emil Kraepelin further refined Morel's ideas by developing the concept of "<i>dementia praecox</i>". He described a cluster of symptoms and signs characterized by a specific course and outcome, emphasizing the chronic and deteriorative nature of the illness. Kraepelin's work laid the groundwork for modern understanding, emphasizing the classification of psychiatric conditions based on symptom clusters, progression, and outcomes. In the early 20th century, Swiss psychiatrist Eugen Bleuler introduced the term "<i>schizophrenia</i>", marking a significant shift in the conceptualization of the disorder. He viewed it not as a single disease but as a group of related disorders, which he called the "group of schizophrenias." Bleuler focused on the splitting of cognitive functions—such as thinking, feeling, and behavior—recognizing a broader spectrum of symptoms beyond the purely degenerative model proposed by Kraepelin. The evolution of schizophrenia's conceptualization reflects broader developments in neuropsychiatry, neuropsychopharmacology, and neuroscience. Advances in these fields have refined diagnostic criteria, understanding of neurobiological underpinnings, and treatment approaches. However, the journey to fully understanding schizophrenia is ongoing. The complexities of its causes, manifestations, and treatments mean that its history—and the final chapter of its understanding—remains to be written, as new research continues to challenge and expand upon existing knowledge.

Research on the Construction of Music Recognition Model Based on Improved CNN Convolutional Neural Network

Abstract. In the context of today's informationized society, music recognition technology within the field of intelligent audio processing has received extensive attention and become a research focus. However, traditional music recognition techniques are difficult to adapt to the complex changes of music signals due to the inherent defects in feature extraction and model construction. To address these difficulties, this study constructs an innovative music recognition algorithm, which is based on an optimized convolutional neural network (CNN). The efficacy of feature extraction is enhanced by fusing the hash convolutional neural network (Hash-CNN), and the temporal data is processed using the long short-term memory network (LSTM) to improve the accuracy of recognition. In the preprocessing stage of music signals, we applied various noise reduction and normalization means to enhance the data quality to a high standard. According to the experimental data, the model performs well in recognizing complex music segments, especially when analyzing multi-level and multi-dimensional music features, it shows strong robustness. Meanwhile, compared with traditional techniques, the model proposed in this study shows significant improvement in both recognition efficiency and accuracy, confirming its great potential and broad prospect in practical applications.

Facilitating Cathode Regeneration via Defect‐Driven Prelithiation

AbstractDirect regeneration of electrode materials has been in the spotlight due to its potential resource recovery and environmental benefits, especially for LiNixCoyMnzO2 (NCM) cathode materials. Yet, prior studies have predominantly emphasized innovating regeneration methods, overlooking the intrinsic defects of spent NCM and their effects in the regeneration process. This study proposes a mechanism aimed at facilitating lithiation regeneration by modulating the surface defects of spent NCM. The generation of oxygen defects in degraded NCM intensifies the adsorption of lithium source, effectively reducing the energy barrier for Li+ migration from surface to bulk. Simultaneously, mechanical energy is employed to alter the local thermodynamic state to provide a driving force for lithium migration, allowing it to undergo a prelithiation reaction before roasting. The temperature range in which the phase transition occurs during the roasting process becomes more concentrated. This contributes to increasing opportunities for lithium insertion and accelerates the repair of crystal structure, resulting in favorable properties of regenerated materials. This strategy innovatively exploits the inherent defects of spent NCM, proposes the critical role of synergistically regulating defect kinetic and thermodynamic features in facilitating regeneration, providing a unique perspective for the design of direct NCM regeneration technology.

Preparation and electrochemical performance of PPyNTs/NiCo-LDH for asymmetric supercapacitors

Supercapacitors possess remarkable benefits in terms of electrochemical energy storage, whereas the inherent defects, such as suboptimal power density, limit commercial employment. Here, NiCo double hydroxide (NiCo-LDH) nanosheets with ZIF-67 as the precursor were fabricated and anchored on the surface of polypyrrole nanotubes (PPyNTs) to prepare composite electrode materials (PPyNTs/NiCo-LDH). Electrochemical test results show that the electrode material possesses 1802 F g−1 specific capacitance under a 1 A g-1 current density. Furthermore, it shows a retention of 50.2 % for capacitance after 5000 cycles with 10 A g-1 current density. To examine the practical performance of the materials, aqueous asymmetric supercapacitors PPyNTs/NiCo-LDH//AC were assembled, with up to 115 F g−1 specific capacitance at 1 A g-1 under a stabilized output voltage of 1.5 V, and possessing a high energy density of 35.94 Wh kg−1 at a power density of 760.2 W kg−1. Meanwhile, the capacitance retention of 65.3 % after 5000 cycles.

MXene-CNT composite Ni12P5 for lithium-sulfur battery performance enhancement

Lithium-sulfur batteries have hindered industrialization due to their inherent defects. In this study, MXene and CNT composite Ni12P5 were used as cathode materials for lithium-sulfur batteries. MXene is known to have high specific surface area, while the CNT composite Ni12P5 has excellent electrical conductivity. The results show that MXene-CNT@ Ni12P5 composite can significantly improve the performance of lithium-sulfur batteries. The composite helps to mitigate the volume expansion and shuttle effect of the sulfur cathode, thereby improving the diffusion efficiency and cycling stability of the battery. In addition, the incorporation of the composite material enhances the electrical conductivity of the battery, reduces the secondary reaction with the electrolyte, and mitigates the deposition of polysulfides during lithium-ion charging and discharging, thereby further improving the lithium-ion diffusion efficiency. Therefore, this study presents a novel and convenient method to enhance the cathode material of lithium-sulfur batteries, which offers a broad prospect for its application in this field.

Generalized composite multiscale improved diversity entropy and its application to diesel injector fault feature extraction and diagnosis

The diesel injector is the core component of marine diesel engines, and its health monitoring is one of the keys to ensuring the efficient and reliable operation of diesel engines and even ships. However, extracting effective feature information from nonlinear dynamic signals is the difficulty in realizing intelligent fault diagnosis of diesel fuel injectors. The existing diversity entropy (DE) is an advanced algorithm for extracting fault features. Still, it has the problem of failing to obtain sufficiently effective fault features, thus affecting diagnostic accuracy due to its inherent defects. To solve the above problem, a new generalized composite multiscale improved diversity entropy (GCMIDE) is first proposed, and the comparative advantages of the proposed entropy in terms of consistency, robustness, and computational efficiency are verified with common noise-simulated signals. GCMIDE is further utilized as an excellent means of feature extraction, and a new injector fault diagnosis method, GCMIDE-Relieff-SSA-BP, is proposed to meet the needs of efficiency and practicality in fault diagnosis. Finally, the method is adopted for the diagnostic experiments of diesel fuel injectors with different fault types and different fault degrees for full validation. The experimental results all indicate that, in comparison with six commonly used entropy-based fault diagnosis methods, the proposed method has the best feature extraction performance and fault diagnosis accuracy under a different number of features or different training sample ratios. This provides an effective tool for fault diagnosis of injectors and even intelligent operation and maintenance of diesel engines.

Advanced Preparation Methods and Biomedical Applications of Single-Atom Nanozymes.

Metal nanoparticles with inherent defects can harness biomolecules to catalyze reactions within living organisms, thereby accelerating the advancement of multifunctional diagnostic and therapeutic technologies. In the quest for superior catalytic efficiency and selectivity, atomically dispersed single-atom nanozymes (SANzymes) have garnered significant interest recently. This review concentrates on the development of SANzymes, addressing potential challenges such as fabrication strategies, surface engineering, and structural characteristics. Notably, we elucidate the catalytic mechanisms behind some key reactions to facilitate the biomedical application of SANzymes. The diverse biomedical uses of SANzymes including in cancer therapy, wound disinfection, biosensing, and oxidative stress cytoprotection are comprehensively summarized, revealing the link between material structure and catalytic performance. Lastly, we explore the future prospects of SANzymes in biomedical fields.

Charge Dynamics and Defect States under “Spot‐Light”: Spectroscopic Insights into Halide Perovskite Solar Cells

Halide perovskite solar cells (PSCs) have shown remarkable power conversion efficiencies. However, the inherent defect issues of perovskite materials still limit their performance and long‐term stability, resulting in lifespans far from commercial standards. With their noninvasive approach to probing the electronic and vibrational properties of materials, spectroscopic techniques have become crucial tools for uncovering and understanding defect states and complex charge carrier dynamics in halide perovskites. This review explores the application of various advanced spectroscopic techniques in PSCs to elucidate the complex behaviors of charge carriers within PSCs. These techniques reveal detailed temporal and spatial distributions of charge carriers, enabling precise analysis of defect impacts and interfacial charge transfer processes. By integrating spectroscopic data, it is possible to more accurately identify and mitigate defect‐induced nonradiative recombination and charge transfer, thereby enhancing the stability and efficiency of PSCs. This comprehensive spectroscopic understanding is crucial for developing innovative technologies to accelerate the commercial viability of PSCs.

Achieving over 10 % efficiency in kesterite solar cells via selenium-free annealing

The unsatisfactory crystalline quality of the absorber layer has seriously impeded the development of kesterite photovoltaic devices, including a small grain size, a typical multi-layer structure, and inherent defects and defect clusters. Herein, we simultaneously modify the nature of the absorber bulk and the heterojunction interface by sputtering quaternary alloy targets and subsequent selenium-free annealing to improve the photovoltaic performance of Cu2ZnSnSe4 (CZTSe) solar cells. By adjusting the sputtering power, the elemental content and distribution in the precursor film are effectively controlled, which helps to obtain a single-layer large grain CZTSe absorber layer with better homogenization and compactness. The harmful inherent defects are significantly suppressed by such a modification. Simultaneously, the widened depletion width and enhanced built-in electric field, as well as improved band alignment at the heterojunction, enhance carrier collection. As a consequence, the efficiency of CZTSe solar cells has improved greatly from 6.91 % to 10.12 %. The single-target preparation strategy without selenization provides a simple and novel perspective for simultaneously adjusting the morphology and defects of kesterite photovoltaic materials, paving the way for promoting innovative industrial applications.

Linear and nonlinear ultrasound parameters attributed to anisotropy in granite

The anisotropic nature of granite, a key factor affecting its mechanical properties, is inherently governed by its mineral alignment and the presence of orthogonal cleavage planes: rift, grain, and hardway. This study examines how these cleavage planes influence anisotropy, particularly in the context of microcracking formation and acoustic properties. A new measurement procedure for the acoustic nonlinearity parameter (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\beta\\:$$\\end{document}) is developed to address the well-known limitations of conventional linear ultrasound methods, including wave velocity and attenuation coefficient, in detecting microstructural changes induced by existing cleavage planes. Unlike other parameters, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\beta\\:$$\\end{document} exhibits remarkable changes depending on the plane type, highlighting its high sensitivity to the mineral distribution in each cleavage plane and to the microcracks. A correlation between the linear and nonlinear parameters provides further evidence of the superiority of \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\beta\\:$$\\end{document} in detecting inherent microscale defects that develop in each plane and affect the anisotropic characteristics of granite. The findings of this study confirm that nonlinear ultrasound is capable of elucidating the mechanisms underlying the origin of anisotropy in granite due to microcracks, with broader implications for understanding unidentified chemical and mechanical phenomena in geological materials.

Quantitative Defect Analysis in CVD‐Grown Monolayer MoS2 via In‐Plane Raman Vibration

ABSTRACTThe synthesis of two‐dimensional transition metal dichalcogenide (2D‐TMD) materials gives rise to inherent defects, specifically chalcogen vacancies, due to thermodynamic equilibrium. Techniques such as chemical vapor deposition (CVD), metal‐organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), flux growth method, and mechanical exfoliation produce large‐scale, uniform 2D TMD films, either in bulk or monolayers. However, defects on the film surface impact its quality, and it is necessary to measure defect density. The phonon confinement model indicates that the first‐order Raman band frequency shift depends on defect density. Monolayer Molybdenum disulfide (MoS2) exhibits three phonon dispersions at the Brillouin zone edge (M point): out‐of‐plane optical phonon vibration (ZO), in‐plane longitudinal optical phonon vibration (LO), and in‐plane transverse optical phonon vibration (TO). The LO and ZO modes overlap with Raman in‐plane vibration (𝐸12g) and Raman out‐of‐plane vibration (𝐴1g), respectively, causing peak broadening. In the presence of defects, the Raman 𝐸12g vibration energy decreases due to a reduced restoring force constant. The Raman 𝐴1g vibration trend is random, influenced by both restoring force constant and mass. The study introduces a quantitative defect measurement technique for CVD‐grown monolayer MoS2 using Raman 𝐸12g mode, employing sequential data processing algorithms to reveal defect density on the film surface.

Microstructure characterization and corrosion performance of an AlMgScZr selective laser-melted component prepared via plasma electrolytic oxidation: Effect of processing time

An AlMgScZr selective laser-melted component was prepared as a ceramic coating via plasma electrolytic oxidation (PEO) technology, which lays a foundation for the component's application in satellite and aircraft components. The inherent small holes and defects of Cl− ions were quickly filled, and the ions attacked the coatings, reducing their corrosion resistance and affecting the component's surface properties. After PEO processing, coatings with a uniform surface and depth were obtained. The contents of Zr, Mg, and Sc in the compact layer near the substrate surface were higher than those in the loose layer of the coatings. The substrate participated in PEO and produced γ-Al2O3 and ringwoodite (Mg (SiO4)). The coatings' roughness, Sa, increased from 1.9 ± 0.7 μm to 3.9 ± 0.3 μm. Hardness increased from 343 ± 20 HV to 691 ± 20 HV. The corrosion potential increased from −1.346 ± 0.005 V vs. SCE to −0.395 ± 0.009 V vs. SCE, and the corrosion current density decreased from 2.275 ± 0.001 × 10−4 A/cm2 to 3.91 ± 0.09 × 10−7 A/cm2. Sc reduced the corrosion performance of the coatings, but a low Sc content has a small effect on the coatings' corrosion resistance. The corrosion product of the coatings obtained after soaking for four weeks was a mixture of Al2O3·H2O and AlCl3.