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Progress in Natural science:Materials International 2014年第5期24卷 531-538页

作者： s.naddaf dezfuli Zhigang Huan J.M.C.Mol M.A.Leeflang Jiang Chang Jie Zhou Department of Biomechanical Engineering Delft University of Technology Biomaterials and Tissue Engineering Research Center Shanghai Institute of Ceramics Chinese Academy of Sciences Department of Materials science and Engineering Delft University of Technology

The human body is a buffered environment where p H is effectively maintained. HEPEs is a biological buffer often used to mimic the buffering activity of the body in in vitro studies on the degradation behavior of magnesium. However, the influence of HEPEs on the degradation behavior of magnesium in the DMEM pseudo-physiological solution has not yet been determined. The research aimed at elucidating the degradation mechanisms of magnesium in DMEM with and without HEPEs. The morphologies and compositions of surface layers formed during in vitro degradation tests for 15–3600 s were characterized. The effect of HEPEs on the electrochemical behavior and corrosion tendency was determined by performing electrochemical tests. HEPEs indeed retained the local p H, leading to intense intergranular/interparticle corrosion of magnesium made from powder and an increased degradation rate. This was attributed to an interconnected network of cracks formed at the original powder particle boundaries and grain boundaries in the surface layer, which provided pathways for the corrosive medium to interact continuously with the internal surfaces and promoted further dissolution. surface analysis revealed significantly reduced amounts of precipitated calcium phosphates due to the buffering activity of HEPEs so that magnesium became less well protected in the buffered environment.

关键词： Magnesium Intergranular corrosion HEPEs DMEM Local pH

Crystalline texture evolution, control of the tribocorrosion behavior, and significant enhancement of the abrasion properties of a Ni-P nanocomposite coating enhanced by zirconia nanoparticles

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International Journal of Minerals,Metallurgy and Materials 2019年第8期26卷 1020-1030页

作者： Masoud sabzi saeid Mersagh dezfuli Zohre Balak Young Researchers and Elite Club Dezful BranchIslamic Azad UniversityDezful ***Iran Department of Materials science and Engineering Science and Research BranchIslamic Azad UniversityTehran ***Iran Department of Materials science Islamic Azad UniversityAhwaz ***Iran

This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured *** the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on st52 steel via the electroless *** electron microscopy(TEM),field emission scanning electron microscopy(FE-sEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDs),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited *** results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.

关键词： Ni-P nanocomposite coatings ZrO2 nanoparticles crystalline texture corrosion resistance abrasive properties tribocorrosion behavior

Effect of Al_2O_3 and Y_2O_3 on the corrosion behavior of ZrO_2-benzotriazole nanostructured coatings applied on AA2024 via a sol–gel method

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International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1344-1353页

作者： saeid Mersagh dezfuli Ali shanaghi saeid Baghshahi Department of Materials science and Engineering Tehran Science and Research BranchIslamic Azad University Materials Engineering Department Faculty of EngineeringMalayer University

zirconia-based nanostructured coatings were deposited on AA2024 to improve the corrosion resistance properties. Three different nanostructured coatings, namely, zirconia–benzotriazole, zirconia–alumina–benzotriazole, and zirconia–yttria–benzotriazole, were applied on AA2024 via a sol–gel method using the dip-coating technique. Next, the coatings were annealed at 150°C after each dipping period. The phases and morphologies of the coatings were investigated using grazing incidence X-ray diffraction(GIXRD), Fourier transform infrared spectroscopy(FT-IR), field emission scanning electron microscopy(FEsEM), and atomic force microscopy(AFM). The corrosion properties were evaluated using electrochemical methods, including polarization and electrochemical impedance techniques in 3.5 wt% NaCl solution. The obtained results confirm the formation of homogeneous and crack free zirconia-benzotriazole-based nanostructured coatings. The average roughness values for zirconia-benzotriazole, zirconia-alumina-benzotriazole, and zirconia-yttria-benzotriazole nanostructured coatings were 30, 8, and 6 nm, respectively. The presence of alumina as a stabilizer on zirconia coating was found to have a beneficial impact on the stability of the corrosion resistance for different immersion times. In fact, the addition of alumina resulted in the dominance of the healing behavior in competition with the corrosion process of zirconia-benzotriazole nanostructured coating.

关键词： zirconia hybrid coatings alumina yttria AA2024 sol-gel corrosion behavior

Effect of melting temperature on microstructural evolutions, behavior and corrosion morphology of Hadfield austenitic manganese steel in the casting process

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International Journal of Minerals,Metallurgy and Materials 2018年第12期25卷 1431-1438页

作者： Masoud sabzi sadegh Moeini Far saeid Mersagh dezfuli Young Researchers and Elite Club Dezful Branch Islamic Azad University Department of Mechanical Engineering Islamic Azad University Department of Materials science and Engineering Islamic Azad University

In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO_2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500°C, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy(sEM) and X-ray diffractrometry(XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy(EIs) in 3.5 wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The sEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.

关键词： Hadfield steel casting process melting temperature microstructural evolutions corrosion behavior corrosion morphology

Effect of 2-mercaptobenzothiazole concentration on sour-corrosion behavior of API X60 pipeline steel:Electrochemical parameters and adsorption mechanism

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International Journal of Minerals,Metallurgy and Materials 2022年第2期29卷 271-282页

作者： Masoud sabzi Amir Hayati Jozani Farzad Zeidvandi Majid sadeghi saeid Mersagh dezfuli Young Researchers and Elite Club Dezful BranchIslamic Azad UniversityDezfulIran Department of Materials science and Engineering Science and Research BranchIslamic Azad UniversityTehranIran Center of Excellence for surface Engineering and Corrosion Protection of Industrial School of Metallurgy and Materials EngineeringCollege of EngineeringUniversity of TehranP.O.Box 11155-4563TehranIran

We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)s at 25°C and in the presence of 0,2.5,5.0,7.5,and 10.0 g/L of 2-mercaptobenzothiazole *** examine this behavior,we conducted open-circuit potential(OCP),potentiodynamic polarization,and electrochemical impedance spectroscopy(EIs)*** dispersive spectroscopy and scanning electron microscopy were also used to analyze the corrosion *** results of the OCP and potentiodynamic polarization tests revealed that 2-mercaptobenzothiazole reduces the speed of both the anodic and cathodic *** assessment of the Gibbs free energy of the inhibitor(△G_(ads)^(■))indicated that its value was less than-20 kJ·mol^(-1)and greater than-40 k J·mol^(-1).Therefore,the adsorption of 2-mercaptobenzothiazole onto the surface of the API X60 pipeline steel occurs both physically and chemically,the latter of which is particularly *** addition,as the△G_(ads)^(■)dsvalue was negative,we could conclude that the adsorption of 2-mercaptobenzothiazole onto the surface of the pipeline steel occurs *** EIs results indicate that with the increase in the 2-mercaptobenzothiazole inhibitor concentration,the corrosion resistance of API X60 steel *** analysis of the corrosion products revealed that iron sulfide compounds form on the *** summary,the results showed that an increase in the inhibitor concentration results in a decrease in the corrosion rate and an increase in inhibitory ***,we found that the 2-mercaptobenzothiazole adsorption process on the API X60 steel surfaces in an H2 s-containing environment follows the Langmuir adsorption isotherm and occurs spontaneously.

关键词： API X60 steel sour corrosion 2-mercaptobenzothiazole inhibitor concentration electrochemical parameters environments containing hydrogen sulfide

Fabrication of Al/Al_2Cu in situ nanocomposite via friction stir processing

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Transactions of Nonferrous Metals society of China 2017年第4期27卷 779-788页

作者： M.AZIZIEH D.IRANPARAsT M.A.G.dezfuli Z.BALAK H.s.KIM Department of Materials science and Engineering College of Engineering Ahvaz Branch Islamic Azad University Department of Materials science and Engineering Pohang University of Science and Technology (POSTECH)

The aim of present work is fabrication of Al/Al2Cu in situ nanocomposite by friction stir processing(FsP)as well asinvestigation of FPs parameters such as rotational speed,travel speed,number of FsP passes,and pin profile on the microstructure,chemical reaction,and microhardness of Al based *** Al2Cu particles were formed rapidly due to mechanicallyactivated effect of FsP as well as high heat generation due to Al?Cu exothermic *** microstructure of the nanocompositesconsisted of a finer grained aluminium matrix(~15μm),unreacted Cu nanoparticles(~40nm),and reinforcement nanoparticles *** morphology of Al2Cu is attributed to the local melting during *** diameter has a higher effect on themicrostructure and hardness *** hardness measurements exhibited enhancement by57%compared with the base metal.

关键词： friction stir processing composite materials hardness microstructure surface properties

Evaluation of seasonal Changes in Temperature and Precipitation for Iran Five Provincial Centres during 1960-2017

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Journal of Geoscience and Environment Protection 2020年第12期8卷 77-93页

作者： Akram Hedayati-dezfuli Farahnaz Fazel-Rastgar Atmospheric science and Meteorological Research Centre Tehran Iran York University Toronto Ontario Canada

Climate change is one of the key challenges of our era and it is a threat to sustainable development. Global warming has many meteorological consequences including rising air temperatures across the world. Undoubtedly, human activity has been one of the key factors to global warming followed by increased greenhouse gas emissions which will exacerbate changes in the Earth’s climate variables. so, any research work related to the climate around the world including Iran due to climate change may cause to better understand the cause and effect and make a better adaptation. This study investigates the regional warming in five meteorological stations in central provinces of Iran, based on seasonal changes in precipitation and temperatures over the period of 1960-2017 (study period). The seasonal drought severity based on Palmer index during 1960-2005 was used to monitor the drought intensity in the study areas which are in drought risk situation. The classification of drought severity using Palmer index shows the severe drought intensity in Arak, Qom, semnan, Tehran and Isfahan respectively in all four seasons, especially during fall and summer. The slight changes in the coefficients of seasonal maximum, minimum and mean temperatures have been resulted. According to these results, the highest maximum (minimum) temperature rise has been calculated for Qom (Tehran) station during spring and winter (fall) seasons ~0.44°C (~0.67°C) in a decade during 1960-2017. However, the highest decrease in precipitation over Arak station has been calculated ~13.8 mm in a decade in winter during study period.

关键词： Drought Climate Change Regional Warming Low Rainfall