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Item MICROSTRUCTURAL ANALYSIS AND MECHANICAL PROPERTIES OF THREE-LAYERED STACK OF FSAM AA7075-CU ALLOYS(World Scientific Connecting Great Minds, 2024) Nallusamy, M; Suriyaprakash, M; Kiran, K; Jayachitra, MFriction Stir Additive Manufacturing (FSAM) is a novel solid-state technique which is performed on the basis of Friction Stir Welding (FSW) process. Compared with conventional fusion welding, FSW overcomes welding defects when it is used for joining dissimilar metals. In this study, Friction Stir Additive Manufactured AA7075-Cu alloy is performed on the principle of FSW by which the materials are not melted during the process. The FSW process is performed on the three-layered stack of alloy combinations of AA7075-Cu alloys. The input process parameters, such as axial load, welding feed and rotational speed at different levels, are considered. The effect of mechanical properties, such as microhardness, Ultimate Tensile Strength (UTS) and % elongation, is observed. The microstructure on the welded nugget zone is obtained using Scanning Electron Microscope (SEM). The microhardness of FSAM AA7075-Cu alloys is significantly increased when compared to the microhardness of AA7075 and Cu alloys. The crystalline structure on the welded nugget zone is observed on the microstructure of FSAM AA7075-Cu alloys from SEM microstructures of parent zone as well as welded zone.Item MICROSTRUCTURAL ANALYSIS AND MECHANICAL PROPERTIES OF THREE-LAYERED STACK OF FSAM AA7075-CU ALLOYS(World Scientific Connecting Great Minds, 2023-08-31) Nallusamy, M; Suriyaprakash, M; Kiran, K; Jayachitra, MFriction Stir Additive Manufacturing (FSAM) is a novel solid-state technique which is performed on the basis of Friction Stir Welding (FSW) process. Compared with conventional fusion welding, FSW overcomes welding defects when it is used for joining dissimilar metals. In this study, Friction Stir Additive Manufactured AA7075-Cu alloy is performed on the principle of FSW by which the materials are not melted during the process. The FSW process is performed on the three-layered stack of alloy combinations of AA7075-Cu alloys. The input process parameters, such as axial load, welding feed and rotational speed at different levels, are considered. The effect of mechanical properties, such as microhardness, Ultimate Tensile Strength (UTS) and % elongation, is observed. The microstructure on the welded nugget zone is obtained using Scanning Electron Microscope (SEM). The microhardness of FSAM AA7075-Cu alloys is significantly increased when compared to the microhardness of AA7075 and Cu alloys. The crystalline structure on the welded nugget zone is observed on the microstructure of FSAM AA7075-Cu alloys from SEM microstructures of parent zone as well as welded zone.Item NEW TRANSITION METAL(II) COMPLEXES WITH NAPHTHOATE AND AMINOGUANIDINE-BASED LIGANDS: A COMBINED SPECTROSCOPIC AND THEORETICAL STUDY WITH ITS APPLICATIONS(Taylor & Francis Online, 2022-10-07) Ponnusamy, Kanchana; Natarajan, Arunadevi; Balakrishnan, Prabha Devi; Sankaran, Shanmuga Sundari; Venkatesan, Hemapriya; Ill-Min, ChungA new series of transition metal complexes of Mn(ΙΙ), Fe(ΙΙ), Co(ΙΙ) and Ni(ΙΙ) is synthesized from aminoguanidine and 3-hydroxy-2-naphthoic acid ligands with the formula (N4H7C)2[M{(C10H6(O)(COO)}2]·2H2O. The synthesized complexes were characterized by analytical, spectral and thermal studies. The elemental analysis confirms the composition of the complexes. The XRD studies show that all the complexes are isostructural in nature. The complexes were screened for antimicrobial activity against a Gram-positive, Bacillus subtilis (B. subtilis), and a Gram-negative, Escherichia coli (E. coli), bacterial species. The antibacterial results were concurrent with the output of the DFT investigation of metal complex, showing that the aminoguanidine moiety plays a key role in biological activity. Molecular docking studies have been carried out to identify the binding affinity and the mode of interaction of metal complexes with E. coli protein (2FUM). Further the synthesized complex is used as a single source precursor for preparation of nano metal oxides. The photocatalytic activity was carried out using the metal oxide as catalyst for degradation of dye materials. The metal oxide is found to be an efficient catalyst for degradation of methyl orange dye.Item LIRIOPE PLATYPHYLLA EXTRACT AS A GREEN INHIBITOR FOR MILD STEEL CORROSION IN SULFURIC ACID MEDIUM(Taylor & Francis Online, 2021) Ill-Min, Chung; Venkatesan, Hemapriya; Seung-Hyun, Kim; Kanchana, Ponnusamy; Natarajan, Arunadevi; Subramanian, ChitraThe phytochemical components of the methanol extract of Liriope platyphylla (L. platyphylla) leaves were identified using UHPLC, and their antioxidant activities were studied. The impact of the L. platyphylla extract on the corrosion of mild steel by 1 M H2SO4 was assessed using electrochemical and gravimetric techniques. L. platyphylla exhibited concentration-dependent corrosion protection activity through a mixed-mode adsorption process, as revealed by polarization studies. Impedance measurements indicated the development of a protective film of the inhibitor, which was confirmed by morphology studies at the micro level with scanning electron microscopy (SEM) and at the nano level with atomic force microscopy (AFM). Fourier transform infrared (FT-IR) studies also confirmed the adsorption of the inhibitor film onto the mild steel surface.Item UTILIZATION OF BIOWASTE AS AN ECO-FRIENDLY BIODEGRADABLE CORROSION INHIBITOR FOR MILD STEEL IN 1 MOL/L HCL SOLUTION(Elsevier, 2020-12) Venkatesan, Hemapriya; Mayakrishnan, Prabakaran; Subramanian, Chitra; Manoharan, Swathika; Seung-Hyun, Kim; Ill-Min, ChungThis report focuses on the application of a biodegradable biowaste [human hair-(HHR)], to produce a mild steel corrosion inhibitor. The performance of HHR extract in inhibiting metallic corrosion in 1 mol/L HCl was investigated. The analysis of the metal corrosion behavior using electrochemical and weight loss techniques revealed that HHR exhibits an efficient corrosion-mitigating effect via adsorption on the metal surface following a Langmuir isotherm. Tafel-plot results revealed the mixed-mode corrosion protection behavior of HHR. Surface analysis using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy provided evidence for the precipitation of a protective HHR film on the metal surface.Item CORROSION RESISTANCE OF CISSUS QUADRANGULARIS EXTRACTS ON METAL IN AGGRESSIVE MEDIUM: GRAVIMETRIC AND SURFACE EXAMINATIONS(Rasayan Journal of Chemistry, 2019-09) Anitha, R; Subramanian, ChitraThe corrosion resistance of Cissus quadrangularis in acid and ethanol medium have been investigated by diverse techniques. It has been noticed that as the concentration (2 to 12v/v %) of C. quadrangularis rises the efficiency of the inhibitor also increases. The maximum inhibition efficiencies of 89.45 % and 75.54 % were attained for acid and ethanol extracts respectively. The emergence of a protective layer on the mild steel surface was assessed by electrochemical impedance studies. The influence of the active ingredients in the extracts was examined by GC-MS analysis. The inhibitor adsorption ensued in the protective layer on the surface was analyzed using SEM and AFM.Item ANTICORROSIVE PROPERTY OF SPIRAEA CANTONIENSISIS EXTRACT AS AN ECO-FRIENDLY INHIBITOR ON MILD STEEL SURFACE IN ACID MEDIUM(Taylor & Francis Online, 2019) Ill-Min, Chung; Kathirvel, Kalaiselvi; Asokan, Sasireka; Seung-Hyun, Kim; Mayakrishnan, PrabakaranThe inhibitive performance of methanolic extract of eco-friendly green inhibitor Spiraea cantoniensis (S. cantoniensis) on inhibiting corrosion of mild steel (MS) in 1 M HCl was studied by weight loss, AC-impedance, Fourier transform infrared spectroscopy (FT-IR), Raman, x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), atomic absorption spectroscopy (AAS), and scanning electron microscopy (SEM) analysis. The results showed that the corrosion rate significantly decreased in the presence of the S. cantoniensis inhibitor with a gradual increase in inhibition efficiency at an increased inhibitor concentration. The temperature studies were conducted which included activation energy (Ea), change in enthalpy (ΔH°ads), change in entropy (ΔS°ads), change in free energy (ΔG°ads) and heat of adsorption (Qads). These calculations were helpful to determine the reaction mechanism and proved it as a physisorption type following the Langmuir adsorption isotherm. The analysis of the protective film using FT-IR, Raman, XRD, and SEM analysis clearly showed the potentiality of S. cantoniensis in blocking the MS surface to prevent corrosion by 1 M HCl. The solution analysis via AAS and UV-Vis showed the inhibitive effect of the inhibitor (S. cantoniensis) in both inhibitive and the uninhibitive solution exhibiting the adsorption of the phytochemical molecules on the MS surface.Item ASSESSMENT OF LOW CARBON STEEL CORROSION INHIBITION BY ECO-FRIENDLY GREEN CHAENOMELES SINENSIS EXTRACT IN ACID MEDIUM(The Korean Electrochemical Society, 2018-07-16) Ill-Min, Chung; Venkatesan, Hemapriya; Kanchana, Ponnusamy; Natarajan, Arunadevi; Subramanian, Chitra; Chi-Hee, Youn; Seung-Hyun, Kim; Mayakrishnan, PrabakaranThe impact of methanol extract of Chaenomeles sinensis (C. sinensis) leaves on acid corrosion of low carbon steel was assessed by gravimetric and electrochemical methods. Phytochemical characterization by total phenolic content (TPC), and total flavonoids content (TFC) of the extract was performed. The TPC and TFC concentrations were identified as 193.50 and 40.55 mg/g. Efficiency increased remarkably in the presence of inhibitor and found as concentration dependent. A maximum inhibition efficiency of 93.19% was achieved using 2000 ppm of the C. sinensis inhibitor. Impedance and surface morphology analysis by SEM and AFM revealed that the anticorrosive activity results from the protective film of phytochemical components of C. sinensis extract adsorbed on the metal surface.Item CARICA PAPAYA PEEL MEDIATED SYNTHESIS OF SILVER NANOPARTICLES AND ITS ANTIBACTERIAL ACTIVITY AGAINST HUMAN PATHOGENS(ScienceDirect, 2017-09-28) Balavijayalakshmi, J; Ramalakshmi, VMetallicnanoparticlesaretraditionallysynthesizedbywetchemicaltechniques,inwhichthechemicalsusedarequiteoftentoxicandflammable.Ripecaricapapayapeelisfoundtobeasuitablesourceforgreensynthesisofsilvernanoparticles.Inthepresentwork,acosteffectiveandenvironmentalfriendlytechniqueforthegreensynthesisofsilvernanoparticlesfrom1mMsilvernitrate(AgNO3)solutionthroughtheextractofripeCaricapapayapeelofvariousconcentrations(5ml,10ml,15ml,20ml,25ml)isdescribed.ThesynthesizedsilvernanoparticlesarecharacterizedbyusingtheUV–visabsorptionspectroscopy,FT IR,XRD,SEMandTEM.Theformationofsilvernanoparticlesisconfirmedbysurfaceplasmonresonance,determinedbyUV–visspectraat400–435nm.Theshiftintheabsorptionbandsandvariationinthecalculatedopticalbandgapsforthevariousconcentrationsofpapayapeelsextractsarealsoobserved.TheFT-IRspectrarevealthatanincreaseintheconcentrationofthepapayapeelextractshiftsthebandstohigherwavelengths.TheaveragecrystallitesizeforvariousconcentrationsofpapayapeelextractisobservedfromXRDspectralanalysisandisfoundtobearound16–20nm,whichisingoodagreementwiththeTEManalysis.TheSEManalysisshowsthesphericalstructureofthesilvernanoparticleswithsomeagglomerationforhigherconcentrationsofpapayapeelextract.ThesynthesizedsilvernanoparticlesshowgoodantibacterialactivityagainsthumanpathogenssuchasEscherichiacoliandStaphylococcusaureusandithasmanymedicalapplicationsItem SOYA BEAN OIL BASED POLYURETHANES FOR CORROSION INHIBITION OF MILD STEEL IN ACID MEDIUM(Taylor & Francis Online, 2016) Valarmathi, Eswaramoorthi; Saranya, Jagadeesan; Sounthari, Palanisamy; Parameswari, Kandhasamy; Subramanian, ChitraPolyurethanes synthesized from soya bean oil were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), X-ray diffraction and energy-dispersion X-ray analysis methods. Thermal stability of the polyurethanes was investigated by thermogravimetric analysis. The corrosion inhibition effect of polyurethanes on mild steel in 1 M H2SO4 was studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy methods. The effect of temperature on the corrosion behaviour of mild steel was studied in the temperature range (303–333 K) with optimum inhibitor concentration. The adsorption of the inhibitors was found to obey the Langmuir adsorption isotherm. It was found that the inhibition efficiency increased with increase in concentration but decreased with increase in temperature. The associated activation energy and other thermodynamic parameters such as adsorption–desorption equilibrium constant (Kads), standard free energy of adsorption (ΔG), enthalpy of adsorption (ΔH) and entropy of adsorption (ΔS) were calculated to elaborate the corrosion inhibition mechanism. Surface morphology of the mild steel plate immersed in 1 M H2SO4 was characterized by SEM and AFM techniques.