Faculty Publications

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Subject: search.filters.subject.Aluminum corrosion

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    3-Methyl-4-amino-5-mercapto-1,2,4-triazole as corrosion inhibitor for 6061 Al alloy in 0.5 M sodium hydroxide solution
    (Springer New York LLC barbara.b.bertram@gsk.com, 2011) Kumari, P.D.R.; Nayak, J.; Nityananda Shetty, A.N.
    3-Methyl-4-amino-5-mercapto-1,2,4-triazole (MAMT) was synthesized, and its inhibition action on the corrosion of 6061 Al alloy in 0.5 M sodium hydroxide was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The effect of inhibitor concentration, temperature, and concentration of the corrosion medium on the inhibitor action was investigated. The surface morphology of the metal surface was investigated by scanning electron microscopy (SEM). The inhibition efficiency increased with the increase in the concentration of the inhibitor, but decreased with the increase in temperature. Both thermodynamic and kinetic parameters were calculated and discussed. The adsorption of MAMT on the base alloy was found to be through physisorption, obeying Langmuir's adsorption isotherm. The results obtained from both the techniques were in good agreement with each other. © 2011 ACA and OCCA.
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    Studies on corrosion behavior of 6061 Al—15 vol. pct. SiC(p) composite in HCl medium by electrochemical techniques
    (Allerton Press Incorporation compmg@maik.ru, 2015) Kshama, K.S.; Nityananda Shetty, A.N.
    The micro-galvanic corrosion of SiC reinforced 6061 Al alloys deprives its potential application in the acidic conditions or at high temperatures. Therefore, the corrosion behavior of 6061 Al—15 vol. pct. SiC(p) composite in HCl medium at different temperatures was studied using electrochemical impedance measurements and potentiodynamic polarization curves. The studies revealed that, on increasing the ionic concentration of the medium and temperature the rate of corrosion also increases. Scanning electron microscopic imaging of polished and immersed sample in the medium showed the smooth and uneven morphology respectively. Activation parameters like energy of activation was calculated from Arrhenius plots. Entropy and enthalpy values were derived from the plots of transition state theory equation. © 2015, Allerton Press, Inc.
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    2-(4-(Diethylamino)-2-hydroxybenzyledene) Hydrazinecarboamide as Corrosion Inhibitor on AA2024-T3 Aluminium Alloy in 0.5 M Hydrochloric Acid Solution
    (Pleiades Publishing compmg@maik.ru, 2018) Prakashaiah, B.G.; Nityananda Shetty, A.; Amitharani, B.E.
    A new compound 2-(4-(diethylamino)-2-hydroxybenzyledene) hydrazinecarboamide (DHBHC) was prepared by the condensation of thiosemicarbazide and diethylaminosalicyaldehyde in ethanol–water mixture and its purity was confirmed with IR, H1 and C13 NMR. Anticorrosion properties of this new compound were studied on the aluminium alloy AA2024-T3 in 0.5M HCl solution at 303 K by potentiodynamic polarization, electrochemical impedance spectroscopy and weight loss method. The inhibition efficiency of DHBHC was found to increase with an increase of its concentration. The inhibition efficiency obtained in this study was 96 ± 3% in the presence of 10 × 10?5 M of DHBHC. The surface morphology of the alloy was investigated both in the presence and in the absence of the inhibitor by field emission scanning electron microscopy, 3D profilometry and X-ray photoelectron spectroscopy. © 2018, Allerton Press, Inc.
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    Enhancing tribological performance of Ti-6Al-4V by sliding process
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Kumar, D.; Deepak, K.B.; Muzakkir, S.M.; Wani, M.F.; Lijesh, L.
    The exceptional combination of mechanical, physical, and anti-corrosive properties of titanium alloy Ti-6Al-4 V (Ti64) makes it idle material for the applications, e.g., aerospace, automobile, chemical, medical etc. The tribological performance of the Ti64 can be enhanced by developing a protective layer or coating on its surface. A tribo-oxide protective layer on the surface of Ti64 through rubbing process was developed. For this, the tribological behavior of tribo pair, Ti64 pin-alumina disc was studied under dry ambient condition for diverse loading and sliding speed conditions, using pin on disc experimental set-up. The tribological performance was quantified in terms of coefficient of friction and wear rate. The mechanical properties like nano-hardness and elastic modulus of the pins surface were determined. The tribological behavior were extremely transient and depend greatly on what the surface has precisely experienced. Experimental results revealed that deprived tribological properties and higher oxide layer was selected. To enhance the tribological behavior of deprived tribological behavior, the pin with high oxide layer is used.
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    Electrochemical corrosion behavior of Ti-10V-2Fe-3Al in different corrosive media
    (Wiley-VCH Verlag info@wiley-vch.de, 2018) Arya, S.B.; Bhattacharjee, A.; Roy, M.
    The electrochemical corrosion behavior of Ti-10V-2Fe-3Al in different corrosive media namely, artificial sea water solution, Hank's solution, 0.5 M sulfuric acid, and 0.5 M hydrochloric acid solution has been investigated. Corrosion rates are evaluated using open circuit potential, current time transient, Tafel extrapolation potentiodynamic polarization curves, and electrochemical impedance spectroscopy. The results show that this alloy has lower corrosion rate in alkaline solution due to formation of thick, compact, and stable passive film. In acid solution corrosion rate is higher as the passive film is less compact, porous, and unstable. In general, the material is more active in C1? ion containing solution. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Cyclic Oxidation and Hot Corrosion Behavior of Plasma-Sprayed CoCrAlY + WC-Co Coating on Turbine Alloys
    (Springer New York LLC barbara.b.bertram@gsk.com, 2018) Nithin, H.S.; Vijay, D.; Ramesh, M.R.
    Components in energy-producing systems suffer a variety of degradation processes such as oxidation and molten salt-induced corrosion as a consequence of complex multi-component gaseous environment. Coatings provide a composition that will grow the protective scale at high temperatures having long-term stability. Plasma spraying was used to deposit CoCrAlY + WC-Co composite coatings on turbine alloys of Hastelloy X and AISI 321. The thermocyclic oxidation behavior of coated alloys was investigated in static air and in molten salt (Na2SO4-60%V2O5) environment at 700 °C. The thermogravimetric technique was used to approximate the kinetics of oxidation in 50 cycles, each cycle consisting of heating and cooling. X-ray diffraction and SEM/EDAX techniques are used to characterize the oxide scale formed. Coated alloys showed a lower corrosion rate as compared to uncoated alloys. The coatings subjected to oxidation and hot corrosion showed slow scale growth kinetics. Preferential oxidation of Co, Cr, W and its spinel blocks the transport of oxygen and corrosive species into the coating by providing a barrier, thereby making the oxidation rate to reach steady state. As compared to the substrate alloys, coatings show better hot corrosion resistance. © 2018, ASM International.
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    On the corrosion resistance of some selective laser melted alloys
    (Elsevier B.V., 2018) Suryawanshi, J.; Baskaran, T.; Prakash, O.; Arya, S.; Ramamurty, U.
    The electrochemical corrosion resistances of selective laser melted (SLM) 316 L austenitic stainless steel (SS), 18(Ni) 300-grade maraging steel (MS), and Al-12 wt.% Si (AS) alloy in a 0.1 M NaCl solution at room temperature were evaluated. The effects of laser scanning strategy (single melt vs. checker board styles), post-SLM heat treatment, and corroding surface orientation (with respect to the scan and build directions) on the corrosion behavior were examined. In all cases, results were compared with those obtained on samples with the same compositions, but manufactured using conventional means. The experimental results show that, for the particular set of experimental conditions employed in this study, SLM in general improves the corrosion resistances of Al-12 wt.% Si and stainless steel alloys and degrades the corrosion resistance of the maraging steel, in comparison to the respective corrosion resistances of their conventionally manufactured counterparts. These results are discussed in terms of microstructural refinement and porosity that are common to the SLM alloys. © 2018 Acta Materialia Inc.
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    Effect of grain refinement on material properties of Mg-8%Al-0.5%Zn alloy after the combined processes of multi-direction forging and equal channel angular pressing
    (Institute of Physics, 2019) Naik, G.M.; Anjan, B.N.; Narendranath, S.; S Satheesh Kumar, S.; Preetham Kumar, G.V.
    Establishing the novel microstructure is an effective method to accelerate the applications of magnesium and its alloys. In this work, an Mg-8%Al-0.5%Zn alloy (AZ80 Mg) with ultra-fine-grain (UFG) size of ?1.29 ?m was achieved by the combined processes of multi-directional forging (MDF) and equal channel angular pressing (ECAP). The achieved ultra-fine grain structure made the Mg alloy, owing to inclusive performance as the structural material. The AZ80 Mg alloy with MDF 6 pass followed by two pass ECAP has superior mechanical properties such as ultimate tensile strength (UTS) of 352 MPa and elongation of 11% when compared to as-received Mg alloy. Also, an unprocessed Mg alloy showed the corrosion rate of a 13.28 mm y?1, the corrosion rate of processed Mg alloy could be further decelerated through a change of microstructure obtained from combined processes of MDF and ECAP. This study outstandingly obtained a 94% reduction of corrosion rate after MDF-3P followed by an ECAP-2P (0.77 mm y?1) process compared to as-received Mg alloy. © 2019 IOP Publishing Ltd.
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    Synergistic inhibition effect of trisodium phosphate and sodium benzoate with sodium dodecyl benzene sulphonate on the corrosion of Mg-Al-Zn-Mn alloy in 30% ethylene glycol containing chloride ions
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Medhashree, H.; Nityananda Shetty, A.N.
    The enhanced efficiency of the sodium dodecyl benzene sulphonate (SDBS) by the addition of trisodium phosphate and sodium benzoate on the corrosion inhibition of Mg-Al-Zn-Mn alloy in aqueous ethylene glycol solution (30%) containing chloride ions was studied by potentiodynamic polarization technique and electrochemical impedance spectroscopy method. The combination of SDBS with trisodium phosphate and sodium benzoate resulted in synergistic effects on the inhibition efficiency. The inhibition efficiencies decreased with the increase in the medium temperature. The mixture of inhibitors acted predominantly as anodic types and the adsorption of the inhibitors on the surface of the alloy obeyed Langmuir adsorption isotherm. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
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    Effect of Annealing and Aging Treatment on Pitting Corrosion Resistance of Fine-Grained Mg-8%Al-0.5%Zn Alloy
    (Springer, 2019) Naik, G.M.; Narendranath, S.; Satheesh Kumar, S.S.; Sahu, S.
    In order to study the influence of plastic deformation, annealing and aging treatment on pitting corrosion, the AZ80Mg alloy was subjected to equal-channel angular pressing (ECAP) by route R at 325°C for up to 4 ECAP passes (P) and annealing conditions of 523 K, 623 K and 723 K followed by aging treatment at 6 h and 12 h. A microhardness and corrosion study was accomplished and microstructural evolution was recorded using optical microscopy (OM), scanning electron microscopy and electron backscatter diffraction (EBSD). OM and EBSD analysis showed that a fine-grain microstructure with average grain sizes of 32.87 µm and 6.35 µm was achieved after 2P and 4P of ECAP, respectively. During annealing and aging treatment, the fine-grain Mg alloy revealed that the maximum microhardness and improved corrosion resistance were observed mainly due to redistribution of ?-secondary phases. Specifically, 12 h aged specimens at 523 K represented maximum microhardnesses of about 85 Hv and 87 Hv for ECAP-2P and -4P, respectively. Also, 12 h aging at 723 K appeared preferable for accomplishing enhanced corrosion properties. © 2019, The Minerals, Metals & Materials Society.