Faculty Publications
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Item Characterization of Plasma Sprayed Mn1.0Co1.9Fe0.1O4 Coating on Crofer 22 APU Interconnect for Solid Oxide Fuel Cell Application(Springer, 2023) Naik, M.; Rajasekaran, B.Atmospheric plasma sprayed Mn1.0Co1.9Fe0.1O4 (MCF) coating is regarded as one of the excellent materials in mitigating Cr-evaporation in Crofer 22 APU ferritic steel during high-temperature operation in solid oxide fuel cell (SOFC) conditions. In this study, MCF-coated Crofer steel has been characterized by examining the cross-section of as-sprayed coating. A network of micro-cracks and globular pores was seen in the cross-section analysis. The porosity of as-sprayed MCF coating was 10.93 ± 1.323%. XRD data revealed α-Fe as the major phase in as-received Crofer steel and CoO as the major phase in MCF coating. Micro-hardness measurements of MCF coating was 163.5 ± 1.5 HV0.1N. The measured values revealed strong metallic interlocking between the coating and substrate. Four-probe method employed on MCF coating showed a decrease in resistance as a function of temperature, indicating an increase in electrical conductivity. The spinel coating on Crofer steel was found to be beneficial for SOFC operation. © 2022, The Indian Institute of Metals - IIM.Item Understanding early-stage oxidation mechanism of Crofer 22 APU solid oxide fuel cell steel interconnect using glow discharge optical emission spectroscopy and grazing incidence X-ray diffraction(Elsevier B.V., 2023) Naik, M.; Santhy, K.; Rajasekaran, R.Crofer 22 APU is used as metallic interconnects in stacking solid oxide fuel cells (SOFCs) operated at elevated temperatures (above 700 °C) owing to their excellent oxidation resistance. Understanding the protective layer formation in the initial oxidation stage would be useful for optimizing and designing protective coatings for extended life. Initial stage oxidation of Crofer 22 APU steel using surface analytical tools such as glow discharge optical emission spectroscopy (GD-OES), grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy, and atomic force microscopy (AFM) are studied in the paper. An oxidation test on as-received Crofer 22 APU steel was carried out in a controlled atmosphere (0.01 Pa) in an in-situ high-temperature X-ray diffraction (XRD) stage at 950 °C. Normal XRD showed no indication of oxidation, while GIXRD revealed the formation of two-layer oxides: Top layer spinel MnCr2O4 and fine-grained inner layer Cr2O3, which was confirmed and quantified by GD-OES depth profiling. The Cr2O3 formed initially led to the formation of MnCr2O4 spinel during the initial stage. The rapid diffusion of Mn through the fine-grained Cr2O3 layer results in an increased growth rate of MnCr2O4 spinel on the top of the fine-grained Cr2O3 layer. © 2023 Elsevier B.V.Item Investigation and Performance Evaluation of Novel Single-Switch High-Gain DC-DC Converters for DC Microgrid Applications(Institute of Electrical and Electronics Engineers Inc., 2025) Diwakar Naik, M.; Vinatha Urundady, U.; Naik, M.; Bonthagorla, P.K.This paper introduces a novel single-switch, non-isolated high-gain DC-DC converter for solar photovoltaic (PV) and fuel-cell (FC) applications. These energy sources typically provide a continuous supply of current, necessitating a high-gain DC-DC converter that operates in continuous conduction mode (CCM). This converter draws a continuous input current from the supply and delivers a continuous output current to the load. The performance of the converter is thoroughly analyzed through the development of a state-space model and the derivation of the small signal transfer function, which helps in understanding the converter’s dynamic behavior. Detailed comparisons with existing converters are also presented. Furthermore, an output voltage controller is designed using the k-factor method to effectively regulate the output voltage without requiring a current sensor, even in the presence of input voltage variations. To validate the effectiveness of the converter and its controller, a 150 W prototype was constructed and experimentally verified in a laboratory setting. © 2013 IEEE.Item Energy density comparable with Li-ion batteries from aqueous supercapatteries of PANI/V2O5/SnO2 nanocomposite and its green electrolytes(Elsevier B.V., 2025) Viswanathan, A.; Ramesh, T.P.; Naik, M.; Nityananda Shetty, A.N.The PANI53.85 %: V2O534.62 %: SnO211.53 % (PVS) ternary nanocomposite synthesized by insitu synthesis as supercapattery electrode material has exhibited energy density (E) equivalent to that of Li-ion batteries as the PVS furnishes an impressive E of 114.13 W h kg–1 with a high power density (P) of 2.400 kW kg–1 at 2 A g–1 in real 2 EL-supercapattery cell set up with low potential window (1.2 V) provided by 1 M H2SO4. The energy storage performance resulted by PVS is, a specific capacity (Q) of 684.8 C g–1, at 2 A g–1. The PVS is robust to withstand its energy storage characters up to 13600 cycles at 0.4 V s–1. The Li-ion supercapattery device of PVS made with a green electrolyte exhibited a Q of 672.0 C g–1, E of 112.0 W h kg–1 and P of 1.200 kW kg–1 at 1 A g–1. © 2025 The Authors