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Page : 567 - 583
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- 전고체 리튬이온전지용 실리콘 및 주석 음극 소재의 연구 동향
- All-solid-state Li-ion batteries (ASSLIBs) have emerged as promising next-generation energy storage systems owing to their superior safety, thermal stability, and potential for high energy density. To realize these advantages, the development of high-capacity and stable anode materials is crucial. Graphite anodes, commonly used in con- ventional Li-ion batteries (LIBs), exhibit a low theoretical capacity of 372 mAh g⁻¹, limiting the overall energy den- sity of ASSLIBs. In contrast, Li metal anodes offer a much higher capacity (3,860 mAh g⁻¹) but face challenges such as dendrite growth and interfacial instability. Alloy-based anodes, including Si and Sn, have gained attention because of their abundance, high theoretical capacities (3,579 and 994 mAh g⁻¹, respectively), and moderate oper- ating potentials (0.4 V and 0.5 V vs. Li⁺/Li). Nevertheless, their practical application remains difficult due to severe volume fluctuations during lithiation and delithiation, leading to mechanical failure and interfacial contact loss. To overcome these limitations, diverse strategies—such as structural optimization, interfacial engineering, composite design, prelithiation, and compound modification—have been proposed to enhance the stability and performance of Si- and Sn-based anodes. This review summarizes recent progress and improvement strategies, offering insights for the future development and practical implementation of ASSLIB technologies.
- KEYWORDs : All-solid-state Li-ion battery, Anode, Si-based anode, Sn-based anode, Nanostructure
- AUTHORs : 이영한 · 박철민†
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Page : 584 - 588
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- 이온전지 및 전자기기용 Zn-Mg 합금의 내변색 특성에 미치는 Zr 기반 전해도금의 효과
- This study examines the impact of Zr-based electroplating on the discoloration behavior of Zn-Mg alloy coatings, which are considered for use in aqueous ion-battery electrodes and electronic components. The as-coated Zn-Mg alloy on steel showed significant surface darkening after being exposed to boiling water, sim- ulating a high-temperature and high-humidity environment. To suppress this surface degradation, a Zr–O–Carbon- ate composite film was created through electroplating. In this process, Zr-Carbonate complexes were transformed into hydroxides and then dehydrated to produce a protective surface layer. The resulting film, approximately 500 nm thick, effectively reduced discoloration by limiting the formation of oxide species responsible for darkening. This was evidenced by significantly smaller decreases in lightness (L*) and a more stable surface morphology com- pared to uncoated samples, even after prolonged exposure. These findings indicate that Zr-based electroplating offers a straightforward and effective approach to enhance the environmental durability of Zn-Mg alloys, poten- tially expanding their use in energy and electronic device materials.
- KEYWORDs : Zn, Zn-Mg alloy coated steel, Blackening, Zr plating, Humid environment
- AUTHORs : 황은혜 · 윤태호† · 김성진†
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Page : 1 - 15
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- Effect of Alloy Composition on Pore-widening Induced Structural Evolution and Wettability of Anodic Aluminum Oxide
- Anodic aluminum oxide (AAO) is commonly utilized in functional surface engineering, yet the influence of alloy composition on AAO growth behavior, pore-widening (PW) characteristics, and structural stabil- ity remains poorly understood. This study investigates AAO films formed on Al 1050, Al 3003, Al 5052, and Al 6061 through anodization for 1 hour under identical conditions, followed by PW in phosphoric acid for varying durations. Despite the same anodizing conditions, significant differences were noted in pore diameter, oxide-film thickness, and AAO growth rates based on alloy composition. Al 5052 demonstrated the highest growth and PW rates, while Al 3003 exhibited the lowest. During the PW process, all alloys ini- tially experienced increased porosity and enhanced wettability; however, extended PW led to distinct collapse behaviors of the oxide film that were dependent on the alloy. These behaviors ranged from gradual structural transformation to rapid oxide removal. Notably, wettability enhancement occurred only while a stable porous structure was intact; once the oxide film collapsed or was removed, wettability reverted. These findings indicate that the PW rate and structural stability are governed by different mechanisms, highlighting the critical role of alloy composition in influencing AAO growth, collapse behavior, and wettability.
- KEYWORDs : Aluminum Alloy, Anodic Aluminum Oxide, Pore-Widening, Structural Stability, Wettability
- AUTHORs : Jisoo Kim and Chanyoung Jeong†
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Page : 16 - 25
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- Cr 3+ 화성처리 및 폴리머 코팅한 갈바륨 코팅 탄소강의 전기화학적 특성 및 기계적 특성
- In this study, three coating conditions were applied to carbon steel specimens: (1) galvalume-coated spec- imens, (2) galvalume-coated specimens treated with trivalent chromium (Cr3+) chemical conversion treat- ment (Galvalume+ Cr3+), and (3) polymer top-coated specimens applied over the Galvalume+ Cr3+ treated layer (Galvalume+Top). The electrochemical corrosion behavior, surface morphology, and mechanical properties of each specimen were systematically evaluated to clarify the role of each surface modification step. The electrochemical measurements included monitoring the open-circuit potential, conducting cyclic potentiodynamic polarization tests, and performing Tafel extrapolation analysis to determine corrosion potential and corrosion current density. Surface characteristics were examined to identify coating integrity and defect evolution after testing. Mechanical properties were assessed through scratch and indentation tests to evaluate hardness, adhesion strength, and creep resistance. The results indicated that the Gal- valume+Top specimens exhibited the highest corrosion resistance, characterized by the lowest corrosion current density. The Galvalume+ Cr3+ specimens showed the greatest hardness and excellent creep resis- tance, while the Galvalume+Top specimens demonstrated superior adhesion strength due to the polymer overlayer. Overall, the combined application of Cr3+ chemical conversion treatment and polymer coating effectively enhanced both corrosion resistance and mechanical performance of the galvalume coatings
- KEYWORDs : Carbon steel, Galvalume coating, Trivalent chromium, Polymer coating, Corrosion resistance
- AUTHORs : 현광룡 · 신동호 · 황현규 · 김성종†
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Page : 26 - 32
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- 미량의 Cu 첨가가 HSLA 강재의 CO 포화된 중성 및 2 산성 수용액 내 부식거동에 미치는 효과
- This study investigates the influence of minor Cu addition on the CO2 corrosion behavior of API-grade HSLA steel in CO2-saturated aqueous environments. Two types of steel were examined: one Cu-free and one containing 0.5 wt% Cu, under neutral (pH ≈ 6) and mildly acidic (pH 4.0–4.5) conditions. The methods used included electrochemical LPR measurements, microstructural characterization, and surface analyses. The addition of Cu did not significantly alter the ferritic microstructure but allowed for limited precipitation of metallic Cu. Under neutral conditions, Cu accelerated initial Fe dissolution and the formation of CuO/Cu2O, which suppressed stable FeCO3 deposition and decreased corrosion resistance. In contrast, under mildly acidic conditions, preferential Fe dissolution led to pronounced Cu enrichment at the surface. The resulting Cu and Cu-oxide layers increased the local pH and promoted more stable FeCO3 formation during prolonged immersion, resulting in lower corrosion rates compared to the Cu-free steel. These findings demonstrate that while Cu plays a detrimental role in neutral solutions, it enhances corrosion resistance in acidic CO2 environments, indicating the potential applicability of Cu-microalloyed steel for acidic CO2 transport conditions.
- KEYWORDs : Cu, Alloying element, Steel, CO2, Corrosion
- AUTHORs : 윤성준 · 윤덕빈 · 방혜린 · 루페쉬 페다네카르 · 아시야 자마다르 · 김완근 · 박세민 · 박진성 · 이재원 · 김성진†
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Page : 33 - 41
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- 터빈 액추에이터 오일 계통에서의 윤활유 열화 및 부식 메커니즘
- Hydraulic actuators in gas turbine (GT) inlet guide vane (IGV) systems are crucial for the stable operation of combined heat and power (CHP) plants. This study systematically investigates the internal damage and corrosion behavior of a GT IGV hydraulic actuator recovered after long-term service in a district heating CHP plant. The manifold block, cylinder tube, and piston were disassembled and analyzed to assess the effects of lubricant degradation and water contamination. Visual and cross-sectional examinations revealed localized corrosion pits, oxide accumulation, and uneven material thinning on lubricant-contacting sur- faces, with maximum pit depths measuring 0.18 mm in the manifold block, 0.13 mm in the cylinder tube, and 0.07 mm in the piston. The chromium plating, approximately 18 μm thick, effectively suppressed deg- radation of the cylinder tube; however, localized coating damage led to interfacial corrosion and acceler- ated substrate degradation. Lubricant analysis showed fluctuations in water content, particle contamination, and PQ index, indicating a lubricant environment susceptible to hydrolysis, additive depletion, and tribo- corrosion. These findings demonstrate that monitoring lubricant properties alone is insufficient to accu- rately represent the evolution of internal damage and provide direct experimental evidence linking lubricant degradation and water contamination to the internal corrosion of hydraulic actuators.
- KEYWORDs : Lubrication system, Actuator, Corrosion, Water contamination, Tribocorrosion
- AUTHORs : 송민지 · 이근형 · 김우철 · 김희산 · 이수열†
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Page : 42 - 52
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- 인공신경망을 이용한 S31803 듀플렉스 스테인리스강의 환경변수 변화에 따른 동전위 분극 거동 예측
- This paper presents an artificial neural network (ANN) model designed to predict the potentiodynamic polarization behavior of S31803 duplex stainless steel (DSS) in marine environments. A full factorial experimental design was utilized to gather data on the effects of temperature, salinity, and pH on corrosion behavior. Potentiodynamic polarization (PDP) tests were performed to create a comprehensive database across a wide potential range. The ANN model uses temperature, salinity, pH, and overpotential as input variables, while the output layer predicts the corresponding current density under overpotential. Based on the dataset obtained from the PDP curves, a multilayer ANN model was developed and optimized to fore- cast polarization curves. The optimized ANN model demonstrated high predictive accuracy, with deter- mination coefficients of 0.993, 0.987, and 0.987 for the training, validation, and test datasets, respectively. These results suggest that the proposed ANN model is an effective tool for predicting corrosion behavior, contributing to corrosion monitoring and condition-based maintenance in marine systems.
- KEYWORDs : Artificial neural network, Duplex stainless, Potentiodynamic polarization, Corrosion behavior, Environmental factors
- AUTHORs : 정광후 · 김성종†
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Page : 53 - 62
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- 무전해 니켈 도금된 선박 디젤엔진 실린더 라이너의 캐비테이션 침식 특성
- This study assessed the enhancement of cavitation erosion resistance in gray cast iron, a common material used for marine diesel engine cylinder liners, through the application of electroless nickel plating (ENP). EDS and XRD analyses revealed that the ENP coating contained approximately 6.4 wt% phosphorus and displayed broadened Ni diffraction peaks, suggesting an amorphous or microcrystalline structure. Cavita- tion erosion tests were performed following ASTM G32 standards using an ultrasonic vibratory apparatus set to an amplitude of 50 µm. The gray cast iron substrate exhibited a rapid increase in cumulative weight loss with exposure time, reaching about 1.2 mg after 90 minutes, along with a significant rise in surface roughness and maximum damage depth. In contrast, the ENP-coated specimen showed a much slower rate of material loss, with cumulative weight loss limited to approximately 0.4 mg even after 240 minutes. Three-dimensional surface profiling further confirmed that the ENP coating effectively inhibited the growth and coalescence of erosion pits, resulting in lower surface roughness and shallower damage depth compared to the substrate. These findings indicate that ENP is an effective surface treatment for improv- ing the cavitation erosion resistance and durability of marine diesel engine cylinder liners in coolant envi- ronments.
- KEYWORDs : Marine diesel engine, Electroless nickel plating, Cavitation erosion, Gray cast iron, Weight loss
- AUTHORs : 박일초 · 전우석 · 한민수†
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