Browsing by Author "Jegadeeswaran, N."

Filter results by typing the first few letters
Now showing 1 - 9 of 9
  • No Thumbnail Available
    Item
    Charactersation & hot corrosion studies on plasma sprayed (WC-CO) / (CR3C2-NICR) Coating on titanium & special steel alloys
    (IAEME Publication, 2018) Reddy, M.S.G.; Ramesh, M.R.; Nageswara Rao, N.T.; Jegadeeswaran, N.
    A present study is an attempt to evaluate the hot corrosion resistance of plasma sprayed 35%(WC-Co)+65 %(Cr3C2-NiCr) coatings on Titanium-15 & MDN 420 alloys in molten salt environment of Na2SO4+60 %V2O5 salt mixture at 700oC under cyclic conditions. The hot corrosion tests are carried out for 50 cycles, for 1 hour each cycle of heating followed by 20 minutes of cooling in open air environment. The tests are conducted in silicon carbide tubular furnace. Thermogravimetric studies are made to establish the kinetics of corrosion for the uncoated and coated samples. The SEM/EDS, XRD & X-ray elemental mapping techniques are made to analyze the parameters like element concentration, morphology, & phase composition & of the hot corrosion products. The parabolic rate constants are evaluated for understanding the corrosion behavior of coatings. It is observed that (WC-Co) + (Cr3C2-NiCr) coated MDN-420 is more resistant than coated (WC-Co) + (Cr3C2-NiCr) coated titanium-15. From the present study it is concluded that the hot corrosion resistance of both the coatings has been attributed to the formation of Ni3V208, NiCr2O4, NiWO4, and COCr2O4 & Cr3C2. © IAEME Publication.
  • No Thumbnail Available
    Item
    Combating corrosion degradation of turbine materials using HVOF sprayed 25% (Cr3C2-25(Ni20Cr)) + NiCrAlY coating
    (2013) Jegadeeswaran, N.; Ramesh, M.R.; Bhat, K.
    High velocity oxy fuel process (HVOF) is an advanced coating process for thermal spraying of coatings on to components used in turbines. HVOF process is a thermal spray coating method and is widely used to apply wear, erosion, and corrosion protective coatings to the components used in industrial turbines. 25% (Cr3C2-25(Ni20Cr)) + NiCrAlY based coatings have been sprayed on to three turbine materials, namely, Ti-31, Superco-605, and MDN-121. Coated and uncoated substrates were subjected to hot corrosion study under cyclic conditions. Each cycle consisted of 1 hour heating at 800°C followed by 20 minutes air cooling. Gravimetric measurements were done after each cycle and a plot of weight gain as a function of number of cycles is drawn. Parabolic rate constants were estimated for the understanding of corrosion behaviour. It was observed that coated Ti-31 and MDN-121 were more resistant compared to the uncoated ones. Uncoated superco-605 was undergoing sputtering during corrosion study and hence comparison between coated and uncoated superco-605 was difficult. The cross-sectional analysis of the corroded, coated samples indicated the presence of a thin layer of chromium oxide scale on the top of the coating and it imparted better corrosion resistance. Parabolic rate constants also indicated that coating is more beneficial to Ti-31 than to MDN-121. © 2013 N. Jegadeeswaran et al.
  • No Thumbnail Available
    Item
    Design and Analysis of Automotive Mufflers for Noise Attenuation in Low and Broadband Frequency Range
    (Informatics India Ltd, 2023) Kumar, S.; Jegadeeswaran, N.; Ramesh, M.R.; Sangamnath, K.R.; Mownesh, G.K.
    Noise pollution is the major drawback of Internal Combustion engines. Automotive engineers and researchers have been working consistently on reducing automotive noise as well as pollution. While designing the mufflers, care must be taken not only for noise reduction but also for back pressure, space constraints, cost incurred, etc. Various methods to design and analyze the mufflers have been devised by researchers across the globe. In this paper an attempt has is made to present a Tuning of muffler for Low and broadband noise. Geometrical parameters influencing design of Helmholtz Muffler has been carried out in this Study. For Broadband noise, impact of Porosity and wool packing material has been chosen as a design parameter. Results observed that for exhaust system with two muffler components we have dedicated Helmholtz chamber, while for exhaust system with single muffler component, internal of muffler to have both broadband and Helmholtz integrated. Reactive mufflers like Two pass mufflers and Three pass mufflers can be taken as an initial reference to have acoustic tuning for both Helmholtz and broadband noise tuning. © 2023, Informatics Publishing Limited and Books and Journals Private Ltd. All rights reserved.
  • No Thumbnail Available
    Item
    Erosion behaviour of HVOF sprayed (CR3C2-35%NICR) +5%Si coatings
    (IAEME Publication, 2017) Somasundaram, B.; Jegadeeswaran, N.; Madhu, G.; Ramesh, M.R.
    In the present study, (Cr3C2-35%NiCr) +5%Si cermet coatings were deposited on a Fe based T22 steel substrate to reduce the damage caused by erosion boiler applications. Erosion studies were conducted on uncoated as well as HVOF coated steels. The erosion experiments were carried out using an air-jet erosion test rig according to ASTM G-76 standard at a velocity of 30 m/s and at different impingement angles of 30°, 60° and 90°. Silica sand particles of size ranging between 150 to180 ?m were used as erodent. Analysis of weight-loss data and volumetric steady state erosion rates for different coatings and substrate alloys are evaluated. The bare T22 steel followed ductile erosion mode where as (Cr3C2-35%NiCr) +5%Si coating exhibited mixed behaviour respectively.
  • No Thumbnail Available
    Item
    Hot corrosion behaviour of HVOF sprayed stellite-6 coatings on gas turbine alloys
    (2014) Jegadeeswaran, N.; Ramesh, M.R.; Sampath, S.; Bhat, K.U.
    The coal burned natural gas in contact with gas turbine can contain impurities of sodium, sulfur, vanadium, silicon and possibly lead and phosphorous, induce accelerated hot corrosion during long term operation. Coatings are frequently applied on gas turbine components in order to restrict surface degradation and to obtain accurate lifetime expectancies. High velocity oxy-fuel thermal spraying has been used to deposit Stellite-6 alloy coatings on turbine alloys. Hot corrosion behavior of the coatings were investigated for 50 cycles of 1 h heating at 800 C followed by 20 min cooling in presence of Na 2SO4 + 50 % V2O5 measuring weight gain (or loss). X-ray diffraction and SEM/EDAX techniques were used to characterize the oxide scale formed. The superior performance of Stellite-6 coating can be attributed to continuous and protective thin oxide scale of CoO, Cr2O3 and SiO2 formed on the surface. The coating region beneath this thin oxide scale was partially oxidized. Uncoated SuperCo-605 and MDN-121 showed less weight gain than Stellite-6 coated samples, but they showed spalling or sputtering during cyclic oxidation. Stellite-6 coating was dense and pore free even after 50 cycles, indicating that it can resist the hot corrosion cycle. © 2013 Indian Institute of Metals.
  • Thumbnail Image
    Item
    Hot corrosion studies on as-received and HVOF sprayed Al2O 3+CoCrAlTaY on Ti-31 alloy in salt environment
    (2013) Jegadeeswaran, N.; Ramesh, M.R.; Bhat, K.U.
    The present investigation is on the High Velocity Oxy-Fuel coating of Ti-31 alloy using fused, blended powder, Al2O3+CoCrAlTaY. Hot corrosion experiments were done on the coated and uncoated Ti-31 under a salt environment of 50% Na2SO4 and 50%V2O 5 at 800�C. Thermogravimetric cycles of 1 hour heating and 20 minute cooling was followed for hot corrosion study. After each cycle weight measurement was carried out. After hot corrosion, the samples were characterized using XRD and SEM/EDS. It was observed that the coated sample is more resistant to hot corrosion than uncoated sample. XRD and SEM analysis indicated that the surface is rich in oxides. Gravimetric analysis indicated that the sample weight gain was following a parabolic relationship with time. A damage mechanism is discussed for the hot corrosion damage of the samples. Presence of high level of chromium in HVOF sprayed coating imparts improved hot corrosion resistance at 800�C, in a molten salt environment of Na2SO4 + V 2O5. � 2013 The Authors. Published by Elsevier Ltd.
  • No Thumbnail Available
    Item
    Hot corrosion studies on as-received and HVOF sprayed Al2O 3+CoCrAlTaY on Ti-31 alloy in salt environment
    (Elsevier Ltd, 2013) Jegadeeswaran, N.; Ramesh, M.R.; Bhat, K.U.
    The present investigation is on the High Velocity Oxy-Fuel coating of Ti-31 alloy using fused, blended powder, Al2O3+CoCrAlTaY. Hot corrosion experiments were done on the coated and uncoated Ti-31 under a salt environment of 50% Na2SO4 and 50%V2O 5 at 800°C. Thermogravimetric cycles of 1 hour heating and 20 minute cooling was followed for hot corrosion study. After each cycle weight measurement was carried out. After hot corrosion, the samples were characterized using XRD and SEM/EDS. It was observed that the coated sample is more resistant to hot corrosion than uncoated sample. XRD and SEM analysis indicated that the surface is rich in oxides. Gravimetric analysis indicated that the sample weight gain was following a parabolic relationship with time. A damage mechanism is discussed for the hot corrosion damage of the samples. Presence of high level of chromium in HVOF sprayed coating imparts improved hot corrosion resistance at 800°C, in a molten salt environment of Na2SO4 + V 2O5. © 2013 The Authors. Published by Elsevier Ltd.
  • No Thumbnail Available
    Item
    Improving Hot Corrosion Resistance of Cobalt Based Superalloy (Superco-605) Using HVOF Sprayed Oxide Alloy Powder Coating
    (Springer India sanjiv.goswami@springer.co.in, 2015) Jegadeeswaran, N.; Bhat, K.U.; Ramesh, M.R.
    Superco-605 is a cobalt based superalloy used widely in the hot section of gas turbines. During their operation, they are exposed to high temperature and molten salt environment, causing damage to the component due to hot corrosion. In this investigation, Superco-605 alloy was coated using a fused oxide alloy powder, $$ 10\,\% {\text{Al}}_{ 2} {\text{O}}_{ 3} + {\text{CoCrAlTaY}} $$10%Al2O3+CoCrAlTaY , using high velocity oxy-fuel process. Coating thickness was in the range of 260–280 µm and it was lamellar in nature. Uncoated and coated samples were subjected to cyclic hot corrosion tests at 800 °C in presence of molten salt environment of $$ {\text{Na}}_{ 2} {\text{SO}}_{ 4}{+}50\% {\text{V}}_{ 2} {\text{O}}_{ 5} $$Na2SO4+50%V2O5. Resistance to hot corrosion was investigated using thermogravimetric analysis, visual observations, X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray spectroscopy. Both samples developed an oxide scale at the top. The uncoated Superco-605 exhibited intense spalling during hot corrosion cycles. The oxide scale on the coated substrate was thin compared to total thickness of the coating. There was a chromium depleted region close to the oxide top scale. An alumina rich layer at the interface of coating-substrate prevents penetration of oxygen into the substrate material. Based on the experimental results, it is concluded that the fused oxide alloy powder is effective in reducing hot corrosion tendency of Superco-605 alloy. © 2015, The Indian Institute of Metals - IIM.
  • No Thumbnail Available
    Item
    Microstructure characteristics and properties of WC-CrC-Ni HVOF coating for boiler tube steel
    (Elsevier Ltd, 2022) Somasundaram, B.; Patil, V.G.; Ramesh, M.R.; Kandaiah, S.; Jegadeeswaran, N.
    In the present work, the characterization of HVOF sprayed WC-CrC-Ni coating on three bare alloys of MDN-310, SA213-T22, and Superfer 800H was investigated with the HVOF technique. The microstructure of the specimens were examined using a range of characterization techniques including XRD analysis, SEM, and EDS interfaced to SEM. The as-sprayed coatings are characterized with respect to microstructure and mechanical properties. The porosity, surface roughness, coating thicknesses, density, and bond strength of coatings have been also evaluated. © 2021