한국부식방식학회

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Page : 418 - 421 DOWNLOAD
슬러리 펌프용 고크롬 주철의 교반 가속 부식법
Stir-accelerated corrosion test of a high chromium cast iron was attempted in 0.1 mol dm-3 H2SO4 + 0.05 mol dm-3 HCl + 10 wt% SiC solution for 48 h at room temperature or at 45 oC. The high chromium cast iron was composed of 2.8 wt% C and 27 wt% Cr and balanced with Fe. The high chromium cast iron was positioned into a 500 mL beaker with stirring of the solution at 1050 rpm using a magnetic hot plate. The corrosion rate was increased by agitating the solution. In addition, the corroded depth of the high chromium cast iron surface was increased by agitating the solution. The surface morphology of the high chromium cast iron after the stir-accelerated corrosion test revealed that a dendritic austenite phase partially remained in the corroded region after agitating the solution, indicating that solution movement during agitating could accelerate the corrosion rate of the high chromium cast iron.
KEYWORDs : High chromium cast iron, Corrosion, Acidic solution
AUTHORs : 이준섭† · 이준형 · 이예진 · 오준석 · 김정구 · 이재현

Page : 412 - 417 DOWNLOAD
Autoxidation Core@Anti-Oxidation Shell Structure as a Catalyst Support for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell
Proton exchange membrane fuel cells (PEMFCs) provide zero emission power sources for electric vehicles and portable electronic devices. Although significant progresses for the widespread application of electrochemical energy technology have been achieved, some drawbacks such as catalytic activity, durability, and high cost of catalysts still remain. Pt-based catalysts are regarded as the most efficient catalysts for sluggish kinetics of oxygen reduction reaction (ORR). However, their prohibitive cost limits the commercialization of PEMFCs. Therefore, we proposed a NiCo@Au core shell structure as Pt-free ORR electrocatalyst in PEMFCs. NiCo alloy was synthesized as core to introduce ionization tendency and autoxidation reaction. Au as a shell was synthesized to prevent oxidation of core NiCo and increase catalytic activity for ORR. Herein, we report the synthesis, characterization, electrochemical properties, and PEMFCs performance of the novel NiCo@Au core-shell as a catalyst for ORR in PEMFCs application. Based on results of this study, possible mechanism for catalytic of autoxidation core@anti-oxidation shell in PEMFCs is suggested.
KEYWORDs : Core shell structure, Autoxidation, Catalyst support, Oxygen reduction reaction, Proton exchange
AUTHORs : Yong-Kang Heo and Seung-Hyo Lee†

Page : 390 - 411 DOWNLOAD
A State-of-the-Art Review of Graphene-Based Corrosion Resistant Coatings for Metal Protection
Any design engineer or coating formulator’s primary objective is to protect metals. Large investments in terms of money, time, labour, and other resources are necessary for constructing large-scale machinery and structures. In terms of economy, the structure’s lifespan should be as long as feasible to create revenue. It is becoming essential to protect metal substrates from corrosion to prolong the lifespan of such huge structures. One of the most exciting, durable, useful, and effective methods to protect metals from corrosion is the application of corrosion-resistant coating. Graphene is a novel material with a wide range of applications because of its extraordinary features. The use of graphene in coating creates an obstacle and complicates the path for corrosive medium to reach the metal. As the path to the metal elongates, the corrosion medium takes longer to reach the metal. Thus, metal corrosion can be avoided. In this paper, the importance of graphene in coating formulation is discussed, including chemical modifications of graphene, the effect of graphene concentration on corrosion inhibition, and the contact angle of coating. This review also highlights the significance of water-based corrosion-resistant coating for preventing environmental damage.
KEYWORDs : Graphene, Corrosion resistance, Water base coating, Metal protection, Corrosive media
AUTHORs : Ganesh S. Zade and Kiran D. Patil†

Page : 381 - 389 DOWNLOAD
Anthocyanins Extracted from Grapes as Green Corrosion Inhibitors for Tin Metal in Citric Acid Solution
Cyclic Voltammetry and weight loss measurements were used to investigate corrosion prevention of tin in a 0.5M citric acid solution containing Anthocyanins extracted from grapes at various concentrations and temperatures. Results showed that the investigated chemicals, Anthocyanins extracted from grapes, performed well as tin corrosion inhibitors in 0.5M citric acid. Increasing the concentration of Anthocyanins increased their corrosion inhibition efficiencies. When the temperature dropped, their inhibition efficiencies, increased indicating that higher temperature tin dissolution predominated the adsorption of Anthocyanins at the surface of tin metal. When inhibitor concentrations were increased, their inhibition efficiencies were also increased. These results revealed that corrosion of tin metal was inhibited by a mixed type of adsorption on the metal surface. The adsorption isotherm of Langmuir governed the adsorption of Anthocyanins. Thermodynamic parameters such as the enthalpy of adsorption, the entropy of adsorption, and Gibbs free energy and kinetic parameters such as activation energy, enthalpy of activation, and entropy of activation were computed and discussed in this study.
KEYWORDs : Corrosion inhibitors, Tin metal, Cyclic Voltammetry, Weight loss, Adsorption
AUTHORs : Mervate Mohamed Mohamed†, Raiedhah Alsaiari, Fatima A. Al-Qadri, Iman Mohammad Shedaiwa, Mabkhoot Alsaiari, Esraa Mohamed Musa, Faeza Alkorbi1 and Ali S. Alkorbi

Page : 372 - 380 DOWNLOAD
토양 매설 배관의 음극방식과 환경인자 간의 상관관계
The external corrosion control of buried pipes can be achieved by a combination of coatings and cathodic protection to maximize effectiveness. One of the factors affecting cathodic protection is the environmental soil conditions. Because soil is a kind of electrolyte, the environmental conditions of soil may be changed by the atmospheric environment. Therefore, in this study, changes in environmental soil factors by atmospheric environmental factors were monitored. In cathodic protection, on-potential and off-potential were measured from December 2021 to July 2022. The effects of external environmental factors and soil environmental factors on cathodic protection were analyzed. Changes in outdoor temperature affected soil temperature, and soil conductivity had a proportional relationship with soil humidity, but outdoor humidity and precipitation did not significantly affect humidity and conductivity of the soil. In contrast, in cathodic protection, the on-potential was affected by temperature, humidity, the conductivity of the soil, and the anode used, but the off-potential was little affected by these factors.
KEYWORDs : Buried pipe, Cathodic Protection, Temperature, Humidity, Conductivity
AUTHORs : 최승헌 · 원석연 · 유영란 · 김영식†

Page : 360 - 371 DOWNLOAD
다구찌 기법을 활용한 통계적·표면 분석에 따른 오스테나이트 스테인리스강의 전해연마조건 최적화 연구
Electropolishing has various parameters because an electrochemical reaction is applied. Accordingly, experiments to determine factors and levels of electropolishing conditions are in progress for various materials. The purpose of this investigation was to optimize conditions for electropolishing using the taguchi method for UNS S31603. Factors such as electrolyte composition ratio, electrolyte temperature, and electropolishing process time were selected. Electropolishing was optimized using analysis of variance (ANOVA), signal-to-noise ratio (the smaller the better characteristics), and surface analysis. Results of ANOVA revealed that only the electrolyte composition ratio among factors was effective for surface roughness. As a result of statistical analysis of the signal-to-noise ratio, the highest signal-to-noise ratio was calculated under electropolishing conditions with sulfuric acid and phosphoric acid ratio of 4:6, an electrolyte temperature of 75 oC, and electropolishing process time of 7 minutes. In addition, the surface roughness after electropolishing under the above conditions was 0.121 μm, which was improved by more than 88% compared to mechanical polishing.
KEYWORDs : Electropolishing, Surface roughness, UNS S31603, Taguchi method, SN ratio
AUTHORs : 황현규 · 김성종†

Page : 348 - 359 DOWNLOAD
전기자동차 배터리 하우징용 6061-T6 알루미늄합금의 전식 특성에 미치는 염화물농도 및 인가전류밀도의 영향
Interest in electric vehicle is on the rise due to global eco-friendly policies. To improve the efficiency of electric vehicles, it is essential to reduce weights of components. Since electric vehicles have various electronic equipment, the research on stray current corrosion is required. In this research, a galvanostatic corrosion experiment was performed on 6061-T6 Al alloy for electric vehicle battery housing using chloride concentration and applied current density as variables in a solution simulating an acid rain environment. As a result of the experiment, when chloride concentration and applied current density were increased, corrosion damage became larger. In particular, pitting damage was dominant at an applied current density of 0.1 mA/cm2. Pitting damage over the entire surface was found at a current density of 1.0 mA/cm2. In conclusion, chloride concentration had a relatively large effect on localized corrosion. The applied current density had a great effect on uniform corrosion. However, in the case of applied current density, localized corrosion was also greatly affected by interaction with chloride.
KEYWORDs : Electric vehicle battery housing, 6061-T6 Al alloy, Stray current corrosion,
AUTHORs : 신동호 · 김성종†

Page : 340 - 347 DOWNLOAD
MMO(Ti/Ru) 코팅된 타이타늄의 고분자 전해질 연료전지 양극환경에서의 전기화학적 거동
In this research, mixed metal oxide (TiO2, RuO2) coating was applied to grade 1 titanium as a bipolar plate for polymer electrolyte membrane fuel cell (PEMFC). Electrochemical experiments were carried out in an aqueous solution of pH 3 (H2SO4 + 0.1 ppm HF, 80 oC) determined by DoE. The air was bubbled to simulate a cathode environment. Potentiodynamic polarization test revealed that corrosion current densities of the titanium substrate and MMO-coated specimen were 0.180 μA/cm2 and 4.381 μA/cm2, respectively. There was no active peak. After potentiostatic experiment, current densities of the titanium substrate and the MMO-coated specimen were 0.19 μA/cm2 and 1.05 μA/cm2, respectively. As a result of observing the surface before and after the potentiostatic experiment, cracked dried clay structures were observed without corrosion damage. Both the titanium substrate and the MMO-coated specimen could not satisfy the interfacial contact resistance suggested by the DoE. Thus, further research is needed before they could be applied as bipolar plates.
KEYWORDs : PEMFC, Bipolar plate, Mixed metal oxide, Ruthenium, Titanium
AUTHORs : 허호성 · 김성종†

Page : 327 - 339 DOWNLOAD
Effect of Water Impingement Conditions on the Degradation of Epoxy Coatings in Tap Water
The water-jet technique started by Bridgman can cut metal and alloys without harmful gas and fume. However, while this technique is convenient to cut metals and alloys, in the case of coated pipe, water jet induces the degradation of coatings on the pipes, and may facilitate structural failure, leakage, and loss of products. While there are many reports on the effect of water jet on cut metals and the damage of metallic materials, research on the effect of water impingement on the epoxy coatings has been little studied. In this work, we therefore control the velocity of water jet, distance between nozzle and specimen, and water temperature, and discuss the effect of water impingement on the epoxy coatings. Increasing water velocity and water temperature and reducing nozzle distance increased the degradation rates of three epoxy coatings were increased. Among three test parameters – water velocity, nozzle distance and water temperature,
water temperature was relatively effective to increase the degradation rate of epoxy coatings.
KEYWORDs : Epoxy coating, Water impingement, Velocity, Nozzle distance, Temperature
AUTHORs : D. H. Kim, Y. R. Yoo, and Y. S. Kim†

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