Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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Author: search.filters.author.Satyanarayan, S.

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    Wetting behavior and evolution of microstructure of Sn-3.5Ag solder alloy on electroplated 304 stainless steel substrates
    (Springer India sanjiv.goswami@springer.co.in, 2012) Nayak, V.U.; Prabhu, K.N.; Stanford, N.; Satyanarayan, S.
    In the present study, wetting characteristics and evolution of microstructure of Sn-3.5Ag solder on Ag/Ni and Ni electroplated 304 stainless steel (304SS) substrates have been investigated. Solder alloy spread on Ag/Ni plated 304SS substrates exhibited better wetting as compared to Ni/304SS substrate. The formations of irregular shaped and coarser IMCs were found at the interface of solder/Ni/304SS substrate region whereas, solder/Ag/Ni/substrate interface showed continuous scallop and needle shaped IMCs. The precipitation of Ag3Sn, Ni-Sn, FeSn2 and lesser percentage of Fe-Cr-Sn IMCs were found at the interface of solder/Ag/Ni/substrate region whereas, solder/Ni/304 SS substrate exhibited predominantly FeSn2 and Fe-Cr-Sn IMCs. Presence of higher amount of Fe-Cr-Sn IMCs at the solder/Ni/304SS substrate interface inhibited the further wetting of solder alloy.
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    Wetting characteristics of sn-0.7cu lead-free solder alloy on copper substrates
    (Trans Tech Publications Ltd ttp@transtec.ch, 2012) Satyanarayan, S.; Prabhu, K.N.
    In the present work, the effect of surface texture on wetting characteristics of lead-free solder Sn-0.7Cu on copper substrates have been investigated at 298°C. The wetting tests were carried out using FTA 200 (First Ten Angstrom) dynamic contact angle analyzer. The surface texture of copper substrate significantly affected the wetting properties of Sn-0.7Cu solder alloy. Contact angles of about 30° were obtained on Cu substrate having smooth surface texture (Ra = 0.0155μm). On other hand contact angles on rough copper surface texture (Ra = 1.1194μm) were reduced to 20°. The contact angles decreased with increasing surface texture of Cu substrate. For rough Cu substrate, it seems that the solder atoms dissolve into the substrate in the time period of 200-600s. © (2012) Trans Tech Publications.
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    Wetting behavior of lead-free solders on copper substrates
    (Institution of Engineering and Technology jbristow@theiet.org, 2013) Satyanarayan, S.; Prabhu, K.N.
    The effect of substrate surface roughness on the wetting behavior of Sn-0.7Cu and Sn-0.3Ag-0.7Cu solder alloys on copper (Cu) substrates was investigated. The contact angles of both solder alloys decreased with increase in substrate surface roughness. The exponential power law (EPL), φ = exp (-Kτn), was used to model the relaxation behaviour of solders. Solder spreading kinetics was successfully represented by the (EPL). EPL parameters (K and n) alloy decreased with an increase in surface roughness. Spreading of solder alloys on both substrates exhibited capillary, gravity and viscous regimes. High spreading rates in the capillary regime, moderate in gravity regime and almost constant rates in viscous regimes were observed.
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    Solder joint reliability of Sn-Cu and Sn-Ag-Cu lead-free solder alloys solidified on copper substrates with different surface roughnesses
    (Trans Tech Publications Ltd ttp@transtec.ch, 2015) Satyanarayan, S.; Prabhu, K.
    In the present work, the bond strength of Sn-0.7Cu, Sn-0.3Ag-0.7Cu, Sn-2.5Ag-0.5Cu and Sn-3Ag-0.5Cu lead free solders solidified on Cu substrates was experimentally determined. The bond shear test was used to assess the integrity of Sn–Cu and Sn–Ag–Cu lead-free solder alloy drops solidified on smooth and rough Cu substrate surfaces. The increase in the surface roughness of Cu substrates improved the wettability of solders. The wettability was not affected by the Ag content of solders. Solder bonds on smooth surfaces yielded higher shear strength compared to rough surfaces. Fractured surfaces revealed the occurrence of ductile mode of failure on smooth Cu surfaces and a transition ridge on rough Cu surfaces. Though rough Cu substrate improved the wettability of solder alloys, solder bonds were sheared at a lower force leading to decreased shear energy density compared to the smooth Cu surface. A smooth surface finish and the presence of minor amounts of Ag in the alloy improved the integrity of the solder joint. Smoother surface is preferable as it favors failure in the solder matrix. © (2015) Trans Tech Publications, Switzerland.
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    Effect of surface treatment on wetting behavior of copper
    (Elsevier Ltd, 2019) Kalgudi, S.; Pavithra, G.P.; Prabhu, N.K.; Koppad, P.G.; Venkate Gowda, C.; Satyanarayan, S.
    Super-hydrophobic surfaces are very useful in cleaning activities. Surfaces with water contact angles above 150° are regarded as superhydrophobic surfaces. In the present study an attempt has been made to achieve superhydrophobicity on copper substrate by electrochemical etching and electro-deposition of Co-Ni alloy and Co-Ni-Graphene composite. A contact angle of about 105° was obtained on Cu surface with electro-deposited Co-Ni alloy and on electro-deposited Co-Ni-G alloy contact angle was found to be 106°. The contact angle was significantly higher at about 142° with electro etched surface. Corrosion test was carried out with electrochemically etched Cu. Electrochemical etching time was varied from 30 to 240 min. The electro-etched Cu substrate etched for 60 min. showed better corrosion resistance with a corrosion rate of 0.197 mm/year. The surface topography of both etched and electrodeposited samples was studied by atomic force microscopy (AFM) and the results were correlated with the wettability data. © 2019 Elsevier Ltd.
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    Robustness Analysis of EV Charging System using Random Forest Algorithm
    (Institute of Electrical and Electronics Engineers Inc., 2023) Barre, U.P.V.; Satyanarayan, S.; Reddy, H.; Pulikala, A.; Bajaj, A.
    Electric cars offer numerous benefits and are considered the future of the automobile industry. However, their worldwide adoption still needs to grow. One of the primary reasons for this delay in electrification is charge anxiety, which refers to the uncertainty customers feel when connecting the charging cable to the car. To address this issue, this study analyses the performance of the charging system using a machine learning model to identify sensitive signals that influence the charging process and can cause successful charging or charge termination. The analysis will also help to define robust operating regions where the charging component can reliably function, regardless of external conditions. This study's findings will provide insights into electric vehicle charging behavior with the supply station. © 2023 IEEE.
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    Lead-free solders for high-temperature applications
    (Association of American Publishers, 2025) Satyanarayan, S.; Narayan Prabhu, K.
    Due to the toxicity of Pb, efforts to develop alternatives to Pb-based solders have been increased significantly. However, only a limited number of lead (Pb)-free solder systems exist for high-temperature applications. In the present paper, a review of the selection of Pb-free solder alloys for high-temperature (300°C–400°C) applications to replace traditional Pb-based alloys is carried out. A discussion on the research and development of high-temperature solder alloys is highlighted in the current review. The solder systems with alloying additions like Au, Sb, Ni and Zn must be investigated to be used as potential candidate materials for high-temperature applications © 2025 by authors.