Faculty Publications
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Item Investigation of microstructural and tribological behavior of Metco 41C+WC-12Co composite coatings sprayed via HVOF process(CRC Press, 2021) Prasad, C.D.; Mathapati, M.; Ramesh, M.R.; Joladarashi, S.The present work deals with developing an elevated-temperature sliding, wear-resistant, iron-based (Metco 41C) composite coating on the boiler steel substrate using high-velocity oxy fuel (HVOF) system. Prior to coating, Metco 41C (70%) and WC-12Co (30%) were mixed mechanically using ball milling process. Later, feedstock was employed into the HVOF system to develop the coating. The coating samples were subjected to metallurgical and mechanical characterization techniques under required conditions. Further substrate and coating were taken for wear test without employing lubrication through pin on disc apparatus. Wear test was carried out by selecting 10 and 20 N loads at room temperature, 200°C, and 300°C parameters. The sliding distance and the velocity were kept constant. The worn-out samples were analyzed for microstructural changes and formation of phases using SEM and XRD methods, respectively. The wear properties of friction coefficient, wear rate, and loss of volume were calculated. Deposited coating exhibited hard phases such as Cr3C2, Ni3C, W2C, Fe2C, and SiC along with intermetallic phases like Mo2C and Co3W3C. The result is improvement in hardness and better wear resistance with respect to the substrate. © 2022 selection and editorial matter, Lalit Thakur, Hitesh Vasudev. All rights reserved.Item Evaluation of microstructural and dry sliding wear resistance of iron-based SiC-reinforced composite coating by HVOF process wear resistance of Fe-based coatings(CRC Press, 2021) Prasad, C.D.; Jerri, A.; Ramesh, M.R.The current work describes the evaluation of microstructural and sliding wear resistance of iron-based composite coatings. The feedstock having (70%) Metco 41C and (30%) SiC were blended mechanically through ball milling process. Further, the prepared feedstock was sprayed by HVOF method on ASTM-SA213-T11 steel substrate. Fabricated coating samples and substrate were characterized on different metallurgical and mechanical methods. The coating and substrate were taken into sliding test using pin on disc tribometer by varying parameters of normal load 10 and 20 N at temperatures 200°C, 300°C as well as room conditions without applying lubrication. The tested samples were analyzed in terms of its microstructural and phase formation using SEM and XRD techniques, respectively. The wear properties such as friction coefficient, loss of material in terms of volume and wear rate of coating and substrate were estimated utilizing system-generated data. The hardness and wear resistance of coating improved due to the existence of hard carbide phases, such as SiC and Fe2C in coating area, were detected. © 2022 selection and editorial matter, Lalit Thakur, Hitesh Vasudev. All rights reserved.Item Clad developments through microwave hybrid heating technique processing and properties(CRC Press, 2022) Suresh, G.; Ramesh, M.R.; Hebbale, A.M.; Srinath, M.S.[No abstract available]Item Surface Engineered Titanium Alloys for Biomedical, Automotive, and Aerospace Applications(Springer Nature, 2023) Gudala, G.; Ramesh, M.R.; Srinath, M.S.This chapter provides an overview of surface modification of titanium alloy for applications in aerospace, automotive, and biomedical field. Current uses for titanium alloys are found in biomedical, automotive, aerospace, and other industrial applications. For aerospace uses, titanium alloys can be used for about 70% of the total, including engine components and airframe structures. Titanium alloys provide a notable advantage in several industrial applications, including heat exchangers, cooling systems in power stations, and chemical industries. In recent times, titanium alloys have been used in oil and gas drilling industries. It was observed that surface degradation of titanium alloy was observed in all the above applications after a certain amount of time or cycle. To enhance the surface properties of titanium alloy, surface engineering of titanium alloy with the appropriate surface modification technique is essential. The present trends predicted that industrial and commercial segments of titanium alloys could triple in the next five years. This chapter presents several case studies involving surface engineering techniques used for titanium alloys for potential automotive, biomedical, and aerospace applications. The demand for applications like the aerospace, biomedical, and automotive industry of titanium alloy boosts the ever-increasing demands for improving the surface modification of titanium alloys to meet the various needs. However, these alloys cannot possess all the desired attributes, especially important surface properties like wear and corrosion resistance. Therefore, surface modification techniques have to be used to enhance surface properties and satisfy the specific needs for various applications. This chapter discusses various surface modification methods used for titanium alloys to protect them from degradation. Titanium and titanium alloys can be extensively used in biomedical components and devices, especially in cardiac and cardiovascular applications, as hard tissue replacements. However, titanium alloys cannot meet all clinical requirements. Surface modification is often required to improve the biological, chemical, and mechanical properties. The present chapter also highlights the various surface modification techniques pertaining to titanium alloys, including thermal spraying, sol–gel, electrochemical treatment, and ion implantation from biomedical engineering. The present study focuses on improving the surface properties of titanium alloy for better wear resistance, corrosion resistance, and other biological properties using appropriate surface modification techniques while the desirable bulk attributes are retained. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Lightweight and sustainable materials for coating applications(Elsevier, 2023) Mathapati, M.; Ramesh, M.R.; Doddamani, M.This chapter deals with the development of Cr3C2-25NiCr/cenosphere/MoS2/CaF2, Cr3C2-25NiCr/cenosphere/MoS2/CaSO4, and Cr3C2-25NiCr coatings through plasma spraying on MDN 321 steel substrate. Methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) are used for coating phase composition and microstructure analysis. Sliding wear behavior of substrate and coatings is tested at 200°C-600°C by utilizing a pin-on-disk tribometer. Owing to the existence of cenospheres and action of solid lubricants, frictional coefficient and wear rate of fly ash cenosphere-based Cr3C2-25NiCr/MoS2/CaF2 and Cr3C2-25NiCr/MoS2/CaSO4 compositions are reduced in comparison with Cr3C2-25NiCr coating and substrate at all test parameters. The characterization of the coatings’ worn-out surface reveals lubrication at 200°C by MoS2. At elevated temperature, CaF2 with CaMoO4 formed through tribochemistry further aids lubrication. Micrographs of worn surfaces demonstrate plowing and delamination as the main wear mechanism. © 2023 Elsevier Ltd. All rights reserved.Item Influence of Impact Angle and Temperature on Solid Particle Erosion Behavior of Titanium-31(Springer Nature, 2024) Behera, N.; Chandramouli, T.V.; Aprameya, C.R.; Ramesh, M.R.The present work shows the effects of impact angles and temperatures on volumetric erosion loss of titanium-31 alloy. An erosion tester was used to perform the erosion tests with temperatures (200, 400, 600, and 800 °C) and impact angles (30°, 60°, and 90°). The alumina particles (Al2O3) are used as an erodent particle with an average particle size of 50 μm. The microhardness, porosity, and surface roughness of titanium-31 alloy are evalu-ated. SEM/EDS and XRD were used to analyze tita-nium-31 alloy eroded samples. The weight loss method and 3D profilometer determined the volumetric erosion loss. The microhardness of titanium-31 alloy is found to be 337 ± 15HV0.3. The Volumetric erosion loss of tita-nium-31 alloy increased with increasing temperatures from 200 to 800 °C, whereas decreased with increasing impact angle from 30° to 90° for all temperatures. The volumetric erosion loss is higher at a 30° impact angle and lower at a 90° impact angle for all temperatures. As a result, titanium-31 alloy shows the ductile erosion mode for all temperatures. The volumetric erosion loss at 30° impact angles is due to micro-cutting and plough-ing, whereas deep crater, groove, and raised lips are for 90° impact angles. The results of volumetric erosion loss obtained by the weight loss method exhibit a good cor-relation with a 3D optical profilometer. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Item Tribological Performance of Fe-Based Composite Coatings Under Elevated Temperature Conditions(Springer, 2025) Chandramouli, T.V.; Joladarashi, S.; Ramesh, M.R.The present study investigated the tribological performance of Fe-based coatings reinforced with carbides onto a maraging steel substrate using the HVOF spray technique. These materials are widely used in manufacturing various components in the aerospace and energy sectors. Commercially available SS316L and 17-4PH are reinforced with WC–Co feedstock powders to deposit these composite coatings on maraging steel substrate. The dry sliding wear tests were conducted using the ball-on-disc tribometer at varying temperatures (25 and 300 °C) with 10 N normal load using an alumina ball (Al2O3) as the counter body. The study includes micro-hardness, porosity, density, bond strength, and surface roughness of the coatings. The samples subjected to wear testing were analyzed using SEM/EDS and XRD techniques, and the wear scar volume was measured using a 3D profilometer to calculate the volume metric loss. The wear rate of SS316L30%WC–Co is 64.46% lower than that of 17-4PH30%WC–Co at room temperature and 67.33% lower at 300 °C under a load of 10 N. At room temperature, the worn surface exhibited abrasive wear, while at 300 °C, adhesive wear and oxidative wear were observed owing to the formation of protective layers. Therefore, SS316L-30%WC–Co demonstrates superior wear resistance compared to 17-4PH-30%WC–Co and offers enhanced mechanical strength, particularly in challenging environments. The deposition of these coatings effectively protects the maraging steel substrate. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Tribological aspects of Al and Mg composites(Elsevier, 2025) Koppad, P.G.; Joladarashi, S.; Ramesh, M.R.; Keshavamurthy, R.It is well known that the technical function of a large number of engineering components/parts depends on motion. However, the term motion here is not as simple as it sounds, because it comes with consequences in the form of friction and wear. Along with lubrication, the science that deals with friction and wear is known as tribology. Therefore, it is necessary to pay more attention to tribology and acquire knowledge on the tribological behavior of materials, as the tribological characteristics such as friction and wear have been causing poor efficiency in engineering structures, huge economic losses, and environmental impacts. One way of addressing these issues lies in the development of lightweight materials based on metals such as aluminum and magnesium. Although one cannot employ these metals in their pure form, but modification in their microstructure and properties can certainly address the needs required for tribological applications. Keeping this in mind, this chapter covers the properties of aluminum and magnesium metals, basic aspects of tribology and most importantly, the work carried out on the friction and wear behavior of aluminum- and magnesium-based composites. The importance of this chapter lies in promoting better knowledge of the tribological behavior of aluminum and magnesium composites, especially from a various wear parameters point of view. The influence of material composition and wear parameters on tribological behavior is covered with a follow-up section on numerical and optimization methods employed for predicting tribological characteristics. © 2026 Elsevier Inc. All rights reserved..Item Investigation on Corrosion Behavior of Polydimethylsiloxane and Nanofillers-Based Polymer Nanocomposite Coated Galvanized Iron(Springer, 2025) Kumar, P.; Kumar, S.; Ramesh, M.R.; Doddamani, M.The paper focuses on developing polydimethylsiloxane (PDMS) and nanofillers (ZnO and SiO2) based polymer nanocomposite solutions for coating galvanized iron (GI) using sol–gel dip coating method and investigating its corrosion behavior. The nanofillers in varying wt.% (0, 2, 4, 6, 8, and 10) are incorporated in the solution of PDMS and xylene for developing a nanocomposite coating solution. The solutions are characterized by pH, viscosity, and non-volatile matter. It is observed that all the solutions are basic. The viscosity (10.28–47.43%) and the non-volatile matter (8.06–15%) of the solutions are observed to be increasing with an increasing nanofiller % as compared to the base solution (PDMS and xylene). The developed solutions are coated on the GI substrate and tested for wettability, XRD, FTIR, and electrochemical responses. The wettability and the XRD tests confirm the hydrophobic and amorphous nature of the coated surface, respectively. The Si–O–Si groups are observed at 1088 cm−1. The electrochemical analysis shows that the impedance resistance of the coated surfaces is higher than that of the surface coated with the base solution. Further, the corrosion rate of the coated surfaces decreases with the % of the nanofillers. The coating with 10% nanofillers exhibited the highest impedance resistance and the lowest corrosion rate, finding applications in construction, marine, and naval. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Effect of ECAP on sliding wear behaviour of Mg-Zn-Gd-Zr alloy(Elsevier Ltd, 2020) Patil, A.; Bontha, S.; Ramesh, M.R.Magnesium is a lightweight, recyclable, and biocompatible material. However, the extensive commercial use of Magnesium and its alloys is hindered by their poor wear behaviour and mechanical properties. Equal Channel Angular Pressing (ECAP) is a severe plastic deformation technique which improves the material properties through grain refinement. In the present study, wear behaviour of ECAP processed Mg-Zn-Gd-Zr alloy was investigated. ECAP process was carried out up to 3 passes at a temperature of 380 °C. Wear testing of as-cast and ECAP processed alloy were carried out using dry sliding wear method on a pin on disk tribometer by varying loads. The wear mechanism was analysed using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). Average Coefficient of Friction (COF) increased after each pass of ECAP. Wear rate increased with the applied load. Despite severe plastic deformation, wear resistance of ECAP processed samples was found to be lower than that of as-cast samples at higher loads. Abrasive and oxidation wear mechanisms were found in both as-cast and ECAP processed samples. © 2019 Elsevier Ltd. All rights reserved.