Faculty Publications
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Item High-temperature wear and frictional behavior of partially oxidized Al with NiCr composite coating(Institute of Physics Publishing helen.craven@iop.org, 2019) Medabalimi, S.R.; Ramesh, M.R.; Kadoli, R.The influence of composite coating in improving wear and frictional behavior from room temperature to 600 °C was investigated. Partially oxidized Al powder was prepared with a flame spray process by spraying pure Al powder into distilled water. The composite powder is the mixture of 30 weight percent of partially oxidized Al and 70 weight percent of NiCr alloy powder. The composite powder was subsequently coated on MDN321 steel by air plasma spray process. The composite coatings are characterized with respect to adhesion strength, porosity, micro-hardness, and density. Wear and frictional behavior of coatings are evaluated under disc speed of 1 and 2 m s-1, loads of 10, 20 and 30 N and 3000 m sliding distance. The test results indicated that at room temperature, frictional heat generated due to applied load produce three-body abrasion at the interface caused to increase the wear and friction in the coating. The oxide film formed at high temperature due to plastic deformation avoids surface degradation at the interface and reduce the wear and friction. The worn surfaces at 600 °C consist phases of ?-Al2O3, NiO, and Cr3O. These phases are contributing to improving the wear resistance of the coating more than 4-times compared to uncoated steels under varying load and sliding velocities. The coefficient of friction reduced with increase in temperature due to generated oxides act as lubricants at the interface. © 2019 IOP Publishing Ltd.Item Studies on free and forced vibration of functionally graded back plate with brake insulator of a disc brake system(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Patil, R.; Joladarashi, S.; Kadoli, R.The back plate with brake insulator of a disc brake system used in automobile is a sandwich structure. Mitigating brake squeal associated with the operation of the disc brake has been a focus of many automobile researchers. As on today’s practice, steel–acrylic–steel is used for back plate–brake insulator assembly. The present study focuses on proposing Al - Al 2O 3 functionally graded metal ceramic composite material (FGM) for the back plate attached with conventional Steel–Acrylic brake insulator. Accordingly, a comparison study is presented in terms of the free and forced vibration characteristics of different material combinations for back plate–brake insulator sandwich beams such as steel–acrylic–steel, FGM–acrylic–steel, FGM–acrylic–aluminium and steel–acrylic–aluminium. The associated governing equations for sandwich beam which are well established in the literature are presented, and they are solved for simply supported conditions using trigonometric displacement functions. The real and imaginary parts of the various parameters come into the picture because of complex shear modulus of viscoelastic core. The comparison study among the combinations reveals that the natural frequency, loss factor and with regard to dynamic loading the imaginary part of transverse displacement, axial displacement, stress and strain of FGM–acrylic–steel are higher. As a result, FGM–acrylic–steel is suitable combination for back plate and brake insulator assembly which enhances the damping capacity of overall disc brake system and also helps in reducing brake squeal problem associated with operation of disc brake system. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Item Solid Particle Erosion Behavior of Partially Oxidized Al with NiCr Composite Coating at Elevated Temperature(Springer, 2021) Subba Rao, M.; Ramesh, M.R.; Kadoli, R.The composite coating was developed and investigated the solid particle erosion performance at elevated temperature by varying impact angles. Al2O3 erodent of grit size 50 µm was used in air-jet erosion tester to investigate the resistance to erosion at RT, 200, 400, 600, and 800 °C by varying 30, 45, 60, 75, and 90° impact angles. The composite coating was deposited on MDN321 steel by plasma spray process with feedstock of “30 weight percent of partially oxidized Al powder and 70 wt.% of NiCr alloy powder.” The composite coating was characterized by bond strength, porosity, micro-hardness, and density. Volumetric erosion loss concerning temperature and impact angle was studied using SEM, EDAX, and XRD analysis. Non-contact three-dimensional optical profilometer was used to quantify the volumetric erosion loss. MDN321 steel showed better erosion resistance than composite coating at all the temperatures. Due to the formation of stable oxides at 800 °C the erosion resistance of the coating was improved. © 2021, ASM International.