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M. Mahmudzadeh,H. Yari,B. Ramezanzadeh,M. Mahdavian 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.78 No.-
Reduction of graphene oxide still is one of discussion subjects in scientific communities. The use of toxicchemicals like hydrazine is a well-known procedure for graphene oxide reduction. In this paper, a newecofriendly, fully scalable, and cheap approach with easy procedure on industrial scale for producingreduced graphene oxide is introduced. The studied method was based on successful reduction ofgraphene oxide by urtica dioica leaves’ extract in 1 h at 90 C. Raman spectroscopy evidenced thesignificant removal of considerable oxygen functional groups in graphene oxide after reduction. Improving corrosion properties by helping the functionalization ability of u. dioica leaves’ extract forsuperior dispersion in polyurethane coatings was studied as well. Electrochemical impedancespectroscopy measurements along with salt spray exposure test revealed the remarkable role ofresultant reduced graphene oxide in protective function of polyurethane coatings before and afteraccelerated weathering condition. Impedance value in low frequency diagrams reveals more than 99%protection efficiency indicating the great role of u. dioica in barrier property of PU coatings afteraccelerated weathering condition.
Corrosion inhibition properties of a green hybrid pigment based on Pr-Urtica Dioica plant extract
M. Motamedi,B. Ramezanzadeh,M. Mahdavian 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-
The main aim of this research is studying the corrosion inhibition properties of the combination of praseodymium nitrate (PrN) and Urtica Dioica (UrDi) on mild steel in sodium chloride solution. Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Vis), thermogravimetric analysis/differential thermogravimetry (TGA/DTG) and X-ray photoelectron spectroscopy (XPS) results confirmed complex formation between Pr cations and UrDi (Pr-UrDi). Electrochemical results revealed that the Pr-UrDi hybrid complex had significant influence on the mild steel corrosion protection (by inhibition efficiency of ca. 94%) in NaCl solution.
Enhancement of silane coating protective performance by using a polydimethylsiloxane additive
M. Mahdavian,B. Ramezanzadeh,M. Akbarian,M. Ramezanzadeh,P. Kardar,E. Alibakhshi,S. Farashi 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.55 No.-
This work intends to study the effect of a polydimethylsiloxane additive on the protection performance of a hybrid silane coating on mild steel. Electrochemical impedance spectroscopy, polarization and electrochemical noise measurements and salt spray showed an increase in corrosion resistance of the silane coating in the presence of the additive. Silane films were examined by FTIR, water droplet contact angle, Vickers hardness and SEM. Results showed decrease in crosslinking density in the presence of the additive. Superior corrosion protection in the presence of additive was attributed to the enhanced hydrophobic character and flexibility of the coating.
Evaluation of cathodic disbondment of epoxy coating containing azole compounds
M. Mahdavian,R. Naderi,M. Peighambari,M. Hamdipour,S.A. Haddadi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Cathodic disbonding of the epoxy coatings on the mild steel was evaluated in 3.5% NaCl solution, wherebenzimidazole, benzothiazole and benzotriazole were used as additives in the coatings. Also, theelectrochemical behavior of coatings delaminating in NaCl solution from a small artificial defect and thebare mild steel samples in the 3.5% NaCl solution containing the azole compounds was evaluated byelectrochemical impedance spectroscopy at cathodic polarization condition. Results showed that theazole compounds were not immobilized in the coating as they could leach out and act as cathodicinhibitor at defect site and disbonding front.
S.M. Orouji,R. Naderi,M. Mahdavian 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.64 No.-
This work aims to study the effect of H2O2 in acid treatment solution on the protective properties of silane coating on mild steel. To this end, different concentrations of H2O2 up to 250 ppm were added to the sulfuric acid solution. The surface morphology, surface roughness, wettability and corrosion behavior of mild steel in the acid treatment solution were studied by SEM, GIXRD, AFM, contact angle, OCP and EIS. Then, a silane coating was applied onto the acid treated samples. It was found that H2O2 at optimal concentration (150 ppm) can improve corrosion protective properties of the silane coating.
M.H. Shahini,Maryam Mousavi,Amir Masoud Arabi,Mohammad Mahdavian,Bahram Ramezanzadeh 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.101 No.-
In this endeavor, ultra-fine Ce oxide QDs were synthesized via an in-situ approach which itself wasdivided into two methods exploited to synthesize QDs on the GO nanosheets. Afterward, the obtainedproduct was loaded into the Epoxy (EP) structure and finally applied on the surface. The results affirmedthe presence of Ce oxide QDs and the quantum confinement effect in both samples. FT-IR analysis confirmedthe presence of different functional groups such as C@C and CAH. UV–Vis outcome showed theinteraction of GO nanosheets and CeO2 QDs. The morphology of the surface, QDs distribution on theGO nanosheets, shape, and particle sizes were explored using FESEM and HR-TEM. Lastly, the corrosionsuppression of different coatings—pure EP, GO-only-containing EP, or EP loaded with quantum-dotsdepositedGO synthesized by two methods—were compared and discussed in detail with the help ofEIS and salt spray methods. The result showed that, in the scratched samples, the maximum Rct of45,080 ohm.cm2 was reached when the QDs-modified GO, attaining via the first method, was employed. The overall result denoted the superior performance of the QDs-modified GO nanosheets embedded inthe EP coating—most specifically the one synthesized with the first method.
Application of Computer Aided Upper Bound Method in Forging and Extrusion Processes
Liu, Gary,Mahdavian, S . M . 대한금속재료학회(대한금속학회) 1998 METALS AND MATERIALS International Vol.4 No.4
This paper presents the development of a Computer Aided Upper Bound software i~or the plain-strain upset forging, and closed impression die processes. The upper bound method is applied by providing the number of plastic sections (triangles). friction conditions of the tool surfaces, and geometry parameters as inputs to a predefined tool and workpiece configuration. The program calculates the funning pressure and provides the upper bound metal flow field and hodograph as outputs. The forming pressure is calculated by an upper bounding algorithm which can be unproved by increasing the number of plastic sections. The differences in tool and workpiece surface friction coefficients and variation of die angles can be considered in order to optimize the forming process.