Faculty Publications
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Item HEA Coatings for Tribo- Corrosion Applications(CRC Press, 2025) Vinay, B.U.; Arya, S.B.High-entropy alloy (HEA) coatings have emerged as a potential solution for addressing the combined effects of mechanical wear and electrochemical degradation that lead to aggravated material failure. Currently used coatings, such as hard ceramic coatings (TiN, CrN, DLC) and thermal spray coatings (WC-Co and NiCrAlY), have problems including instable passive film formation, brittleness, and selective element leaching, which limits their effectiveness in harsh tribo-corrosion environments. HEA coatings can overcome these limitations by leveraging factors, such as multi-element synergy, sluggish diffusion, severe lattice distortion, and self-healing passive films, thereby enabling superior hardness, wear resistance, and corrosion stability. These coatings are particularly suitable for marine propellers, drilling tools, biomedical implants, and aerospace bearings, where frictional wear and corrosive attack occur simultaneously. This chapter explores tribo-corrosion mechanisms in HEA coatings, covering topics such as passive film breakdown, wear-assisted electrochemical reactions, and synergistic degradation effects. Additionally, the chapter discusses advanced fabrication techniques, including laser cladding, thermal spraying, and electrochemical deposition, which enhance tribo-corrosion resistance. Furthermore, this work provides a comparative analysis on subjects, including conventional coatings, experimental findings, and emerging advancements in nanostructured, self-healing, and functionally graded HEA coatings. Finally, future research directions are provided that highlight machine learning-assisted alloy design, in-situ wear-corrosion monitoring, and sustainable HEA formulations, which are expected to advance industrial adoption and long-term durability. © 2026 Taylor & Francis Group, LLC.Item Anti-Corrosion High-Entropy Alloy Coatings(CRC Press, 2025) Vinay, B.U.; Arya, S.B.High-entropy alloy (HEA) coatings have emerged as a potentially revolutionary approach to combating corrosion in extreme environments. Unlike conventional alloy coatings, which rely on a single dominant element, HEAs incorporate multiple principal elements in near-equiatomic ratios, leading to exceptional corrosion resistance, mechanical durability, and thermal stability. The unique core effects of HEAs-high configurational entropy, sluggish diffusion, severe lattice distortion, and the cocktail effect-contribute to their superior performance by enhancing passive film formation, reducing atomic migration, and preventing localized corrosion. This chapter provides a concise overview of the anti-corrosion mechanisms of HEA coatings, discussing the role of alloying elements in passive layer formation and electrochemical stability. Various fabrication techniques-including laser cladding, thermal spraying, magnetron sputtering, and electrochemical deposition-are examined for their effectiveness in producing dense, adherent, and long-lasting HEA coatings. The performance of these coatings in marine, high-temperature, acidic, and biomedical environments is analyzed, highlighting their advantages over traditional stainless steel and nickel-based coatings. Furthermore, the challenges and future directions of HEA coatings are discussed, emphasizing the need for cost-effective processing, scalability, and long-term stability evaluation. The potential of self-healing coatings, nanocomposite HEAs, and functionalized surfaces is explored as promising research directions. With continued advancements in materials science and coating technologies, HEA coatings are poised to revolutionize corrosion-resistant applications in the aerospace, energy, marine, chemical, and biomedical industries. © 2026 Taylor & Francis Group, LLC.Item Corrosion aspects of Al and Mg based composites(Elsevier, 2025) Bhole, K.B.; Arya, S.B.; Nayak, J.Corrosion is a significant concern in various industries, particularly in applications where metal components are exposed to aggressive environments. Aluminum (Al) and magnesium (Mg) are lightweight metals that find extensive use in aerospace, automotive, and structural applications. However, their susceptibility to corrosion limits their widespread adoption in certain conditions. Metal matrix composites (MMCs) have emerged as a promising solution to enhance the corrosion resistance of these metals while maintaining their desirable mechanical properties. The corrosion resistance of pure Al and Mg is often compromised in harsh environments due to galvanic coupling, electrolyte exposure, and chemical reactions. MMCs, where metal works as a matrix while reinforced by ceramic or hard metallic phases, offer a unique property to tailor a required mechanical property along with suitable corrosion resistance. However, it is challenging to control as well as enhance resistance to corrosion in various corrosive environments. The development of advanced metal matrix composites with tailored corrosion resistance profiles holds the key to expanding the application range of Al and Mg in diverse industries, ensuring their longevity and reliability in corrosive environments. A range of electrochemical techniques, including open circuit potential, electrochemical impedance spectroscopy, and polarization resistance test, highlighting their applications are discussed. © 2026 Elsevier Inc. All rights reserved..Item A comparative study of semiconducting behavior of passive film of high nitrogen and Ni and Mn free stainless steels in 3.5 wt. % NaCL(2013) Arya, S.B.; Raja, V.S.; Tiwari, A.N.The semiconducting property of passive films formed on Alloy 1 (18Cr-2Mo-1N), Alloy 2 (17.5Cr-3Mo-0.5N) and Alloy 3 (Type 316 SS) were studied by using the Mott-Schottky (M-S) approach in 3.5 wt. % NaCl solution of pH 2, 7 and 12. The M-S analysis shows that the film acts as n-type and p-type semiconductors across the potential range. The donor density of Alloy 1 has been found to be lower by about 31%, 11% and 6% as compared to that of Alloy 2 at pH 2, 7 and 12 respectively. However, Alloy 3 has higher donor density 44%, 27% and 30% in comparison with Alloy 1. The donor density of Alloy 3 found to be greater about 21%, 18% and 25% to the Alloy 2 at pH 2, 7 and 12 respectively.These results indicate that the sensitivity of electrolyte composition and the presence of alloying elements like nitrogen and nickel on the donor density of passive film. High nitrogen stainless steels exhibited a lower donor density that corresponds to good protectiveness, more stable passive film which is in agreement with a low passive current density (ipass), higher pitting potential (Epit) and polarization resistance (Rp). © (2013) Trans Tech Publications, Switzerland.Item Hot corrosion stability of double perovskite and pyrochlore in suphate solution of vanadates or chlorides at 900 °C(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Baskaran, T.; Sreedhar, G.; Arya, S.B.Double perovskites, pyrochlores are having matching thermal expansion co-efficient with bond coat and may act as candidate materials for an intermediate layer between bond coat and top coat in Thermal Barrier Coatings. Hot corrosion stability of double perovskites and pyrochlores is also important for enhanced thermal cycle life. Based on these issues, systematic studies were conducted to find the hot corrosion stability of double perovskites and pyrochlores. The results revealed that, double perovskites and pyrochlores were undergone destabilization in the Na2SO4+50 wt.% V2O5 and Na2SO4+10 wt.% NaCl environments at 900 °C. The implications of these findings addresses the key issues related hot corrosion mechanisms and give a pathway to developing newer materials. This study clearly indicates the destabilization of both double perovskites and pyrochlores in vanadium and chloride environments at 900 °C. © (2015) Trans Tech Publications, Switzerland.Item EIS study and role of chloride ions concentration and temperature on passivity of AZ91D Mg alloy(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Arya, S.B.; Kanaujia, A.Mg alloy shows higher specific strength and ductility relative to aluminum and also lower machining and casting costs over to steels. However, it also shows limitation to use in many industrial applications due to the relatively poor corrosion resistance in many aqueous solutions. Corrosion and passivation study of magnesium alloy (AZ91D) in various Cl¯ ions concentrations and temperatures were carried out using electrochemical impedance spectroscopy (EIS) in NaCl solutions of 0.4, 0.6, 0.8 & 1.0 molar (M) concentrations. The passivation behavior was also observed at temperature of 45°C, 55°C and 65 °C in 3.5 wt% NaCl solutions. The total polarization resistance was observed about 5530, 4030, 2465 and 2000 Ohms.cm2 in solutions of 0.4, 0.6, 0.8 & 1.0 M NaCl respectively indicate reduction of film stability at higher chlorides concentration. A similar trend was found on increasing temperatures of 3.5 wt% NaCl solutions at 45°C, 55°C and 65 °C and noticed about 970, 600 and 300 Ohms.cm2 respectively showed significant decline of passivity and more pitting tendency. © (2015) Trans Tech Publications, Switzerland.Item Microstructure, mechanical and corrosion properties of accumulative roll bonded Mg-2%Zn/anodized Al-7075 composite(Elsevier Ltd, 2018) Anne, G.; Ramesh, M.R.; Shivananda Nayaka, H.S.; Arya, S.B.Multilayered composite of Mg-2%Zn/anodized Al-7075 was developed by accumulative roll bonding (ARB) of wrought Mg-2%Zn and anodized aluminium 7075 alloy. The Mg-2%Zn/anodized Al-7075 composite exhibited density of 2298 kg/m3 which is about 1.2 times lighter weight as compared to Al-7075 alloy. The electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) showed an average grain size of 1 μm and 0.73 μm in Mg-2%Zn and anodized Al-7075 layers respectively, and with high angle grain boundaries (HAGBs). Mechanical properties were evaluated by microhardness and tensile tests and found significant improvement in strength and hardness values as compared with Mg-2%Zn alloy after four pass ARB process. The multilayered composite shows better corrosion resistance as compared to rolled Mg-2%Zn alloy evaluated using using potentiodynamic polarization test. © 2017 Elsevier Ltd.Item Fabrication of samarium strontium aluminate ceramic and deposition of thermal barrier coatings by air plasma spray process(EDP Sciences edps@edpsciences.com, 2018) Baskaran, T.; Arya, S.B.Thermal barrier coatings (TBC) with the metallic NiCrAlY bond coat are often used in many aircraft engines to protect superalloy components from high-temperature corrosion thereby to improve the life of gas turbine components. The search for new TBC material has been intensified in recent years due to lack of thermo-physical properties of conventionally used Yttria stabilized Zirconia (YSZ) TBCs. Recently, the rare earth containing Samarium Strontium Aluminate (SSA) based ceramic was proposed as a new TBC material due to its matching thermo-physical properties with the substrate. The present work focused on the synthesis of SSA ceramics for TBCs application and its coatings development on Ni-based superalloy Inconel 718 substrate by air plasma spray process. The X-ray photoelectron spectroscopy (XPS) result confirmed the formation of single phase SSA ceramic after synthesis. The surface morphology of SSA TBCs is mainly composed of melted splats, semi and un-melted particles. The cross-sectional SEM micrographs did not show any spallation at the interface which indicated good mechanical interlocking between the bond coat and ceramic top coat. The Young's modulus and hardness of SSA TBCs were found to be 80 and 6.1 GPa, respectively. The load-depth curve of SSA TBC showed good elastic recovery about 47 %. © The Authors, published by EDP Sciences, 2018.Item Role of porosity on electrochemical corrosion behavior of porous Ti-20Nb-5Ag alloy in simulated body fluid(Elsevier Ltd, 2020) Shivaram, M.J.; Arya, S.B.; Nayak, J.; Panigrahi, B.B.Porous titanium alloys are presently well-considered materials for orthopedic applications owing to their superior mechanical properties, excellent biocompatibility and high resistance to corrosion. Also, porous alloys are potentially minimizing the risk of stress-shielding effect as compared to bulk implant materials. In this present work focused to examine electrochemical corrosion behavior of porous Ti-20Nb-5Ag alloy (wt%) with different porosity levels. This designed alloy composition of elemental powders was mixed through mechanically alloying. The mechanically alloyed powder blended with four different amounts of NH4HCO3 (wt%), use to prepare the porous Ti-20Nb-5Ag alloy with porosity ranging from 22% to 68%. After the successful development of porous samples, we investigated the effect of porosity levels on electrochemical corrosion behavior of porous Ti-20Nb-5Ag alloys by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in simulated body fluid (SBF) at 37 °C. The results show that an increasing the trend of porosity level causes a reduction of corrosion resistance. With increasing porosity, the corrosion current density increased and decreases the electrochemical polarization resistance in the SBF solution. © 2019 Elsevier Ltd. All rights reserved.Item Development and characterization of Cu/MWCNT composite prepared by electrodeposition technique(American Institute of Physics Inc. subs@aip.org, 2020) Bharathi, K.D.; Rahman, M.R.; Choudhary, S.; Arya, S.B.Multi walled carbon nanotube (MWCNT) reinforced copper matrix (Cu/MWCNTs) nanocomposites were successfully fabricated by electrodeposition technique using DC-Power source. With various concentrations of CNT, microstructural, micro hardness, tensile stress, and Electrochemical studies were done. The Cu/MWCNT nanocomposites at the highest concentration of 450mg/l exhibited ∼25% and 47% higher tensile strength and Vickers microhardness respectively than that of the pure Cu. Electrochemical AC-impedance and Tafel polarisation analyses confirmed that the corrosion potential (Ecorr) and corrosion current density (icorr) of nanocomposites at 450 «mg/l obtained about 190 »mV SCE and 1.09 μ A/cm2 respectively in 3.5 wt.% NaCl solution. © 2020 Author(s).