Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
9 results
Search Results
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 Elevated temperatures erosion wear behavior of HVOF sprayed WC-Co-Cr/Mo coatings on Ti6Al4V substrate(Elsevier B.V., 2023) Behera, N.; Medabalimi, S.; Ramesh, M.R.The present research aims to investigate the effect of different impact angles and temperatures on volumetric erosion loss of WC-Co-Cr coating containing 10 wt% Mo. The composite coating was developed using High-Velocity Oxy Fuel (HVOF) process on a titanium substrate (Ti-31). A solid particle erosion behavior of the coatings is carried out at different impact angles (30°, 60°, and 90°) and temperatures (200 °C, 400 °C,600 °C, and 800 °C). The volumetric erosion loss of the coated samples was measured using an air jet erosion tester at high temperatures using Al2O3 as an erodent. The XRD, SEM/EDS, porosity, density, microhardness, bond strength, and scratch tests characterized the as-sprayed coatings. The 3D optical profilometer was employed to evaluate the volumetric erosion loss and the mode of erosion. The scratch resistance of WC-Co-Cr coating is better than WC-Co-Cr/Mo coating. The WC-Co-Cr coating shows a brittle mode of erosion up to 600 °C and a ductile mode of erosion at 800 °C. In contrast, the WC-Co-Cr/Mo coating shows a brittle mode of erosion at 200 °C and a mixed mode of erosion at 400 °C to 800 °C. The volumetric erosion loss of WC-Co-Cr is less than WC-Co-Cr/Mo for all temperatures and impact angles. The formation of oxide phases on the coating surfaces demonstrates erosion resistance at high temperatures. The results of volumetric erosion loss measured by the weight loss method correlate well with a non-contact type 3D optical profilometer. © 2023 Elsevier B.V.Item Effect of Impact Angles and Temperatures on the Solid Particle Erosion Behavior of HVOF Sprayed WC-Co/NiCr/Mo and Cr3C2-CoNiCrAlY Coatings(Springer, 2023) Behera, N.; Medabalimi, S.; Ramesh, M.R.Extreme erosion wear from elevated temperature caused by the impact of entrained solid particles in the fluid stream primarily affects aerospace components and marine parts. This work focuses on increasing the base material erosion resistance by applying thermally sprayed carbide-based coatings. A high-temperature Solid particle erosion behavior of WC-Co/NiCr/Mo and Cr3C2-CoNiCrAlY coatings deposited by the HVOF process on a titanium-31 was evaluated using an air-jet erosion tester. The erosion test was conducted utilizing alumina erodent of grit size 35-50 µm. The effects of impact angles (30°, 60°, and 90°) and temperatures (200-800 °C) on the erosion performance of two coatings are compared. The feedstock powder and as-sprayed coatings were characterized for micro-structure phase composition, porosity, density, micro-hardness, and adhesion strength. SEM/EDS and a 3D optical profilometer were used to examine eroded samples further to determine the erosion mode. The Cr3C2-CoNiCrAlY coating shows a brittle mode behavior of erosion at 200-400 °C and ductile mode behavior of erosion at 600-800 °C. In contrast, the WC-Co/NiCr/Mo coating shows brittle mode behavior of erosion at 200-400 °C and 600-800 °C, a mixed mode behavior of erosion. The erosion loss in volume of Cr3C2-CoNiCrAlY is lower than WC-Co/NiCr/Mo for all temperatures and impact angles. The development of carbide and oxide phases on the eroded surfaces demonstrates increasing erosion resistance at high temperatures. The optical profilometer measures the volumetric erosion loss, compares it with the weight loss method, and finds consistency between them. © 2023, ASM International.Item Elevated temperature wear and friction performance of WC-CoCr/Mo and WC-Co/NiCr/Mo coated Ti-6Al-4V alloy(Elsevier Inc., 2024) Behera, N.; Ramesh, M.R.; Rahman, M.R.The effect of adding Mo to WC-based coatings on the microstructure and dry sliding wear performance at elevated temperatures is investigated. The WC-based coatings are deposited using a high-velocity oxy-fuel process on the titanium-31 substrate. The coating was characterized by microstructure, microhardness, porosity, surface roughness, density, and bond strength. The wear and friction behavior of coatings was evaluated using a ball-on disc tribometer at temperatures of 200, 400, 600, and 800 °C and loads of 20 and 30 N. SEM-EDS and an optical profilometer were utilized to evaluate the wear rate and mechanism. The microhardness and bond strength of WC-CoCr/10%Mo coating is more than that of WC-Co/20%NiCr/10%Mo coatings. The WC-CoCr, WC-CoCr/10%Mo, and WC-Co/20%NiCr/10%Mo coatings exhibited decreasing wear rates up to 600 °C, transitioning to an increase at 800 °C. The oxide phases of CoWO4 WO3 MoO3, CoMoO4, and NiMoO4, formed at 600 °C, aid in reducing the rate of wear and friction coefficient. However, the wear rate slightly increased at 800 °C due to vigorous oxidation and softness of coatings. The friction coefficient of WC-CoCr, WC-CoCr/10%Mo, and WC-Co/20%NiCr/10%Mo coating decreases with increasing temperatures due to the lubricating properties of oxide phases on the worn surface. The WC-CoCr/10%Mo coating demonstrates a lower friction and wear rate than the WC-CoCr and WC-Co/20%NiCr/10%Mo coating. At 200 °C, the predominant wear mechanisms were abrasive and fatigue wear, while at 800 °C, oxidative wear, abrasive wear, and adhesive wear were observed. © 2024Item An investigation on tribological performance in HVOF sprayed of Amdry1371 and Amdry 1371/WC-Co coatings on Ti6Al4V(Elsevier B.V., 2024) Behera, N.; Srihari, M.; Sharma, Y.K.; Ramesh, M.R.This study investigates the effect of 30 wt% WC addition into Mo-based coating on the microstructure and dry sliding wear performance at elevated temperatures. A ball-on disk tribometer assessed coating wear and friction behavior at room temperature (RT), 300, and 600 °C with loads of 10 and 20 N. The wear rate and mechanism were assessed using SEM-EDX and an optical profilometer. The coating characteristics included density, porosity, surface roughness, microstructure, and microhardness. The bond strength of Amdry1371 and Amdry1371/30%WC-Co coatings is analyzed using the scratch test. During the scratch test, both coatings show cohesive failure at 30-50 N and cohesive along with adhesive failure at 70 N loads. Compared to Amdry1371 coating, Amdry1371/30%WC-Co coating has greater microhardness and bond strength. The wear rate and friction coefficients of Amdry1371 and Amdry1371/30%WC-Co coatings increase with temperatures up to 300 °C and decrease at 600 °C. Wear debris is generated when contact surfaces fracture under the applied load, acting as a third body in the sliding process. This phenomenon, observable from room temperature to 300 °C, increases wear rate and friction coefficients. Protective oxide phases formed on worn surfaces like MoO3, NiMO4, CoWO4, Cr3O8, and WO3 film at 600 °C. This glaze layer is present on worn surfaces, significantly reducing friction coefficients and the wear rate of coatings. Amdry1371/30%WC-Co coating exhibits superior wear resistance and lower friction coefficients than Amdry1371 coating due to MoO3 and WO3. At RT, the dominant abrasive wear mechanism shifts to oxidative wear at 600 °C for both coatings. © 2024 Elsevier B.V.Item Characterization and evaluation of carbide-based composite coatings for high-temperature wear resistance on Titanium substrate(SAGE Publications Ltd, 2025) Behera, N.; Ramesh, M.R.Titanium alloys are used in the automotive and aerospace industries, but perform poorly at high temperatures due to inadequate wear and friction properties. This study investigates Cr3C2-25%CoNiCrAlY and WC-CoCr coatings applied via High-velocity oxygen Fuel on a titanium-31 substrate. Coatings were evaluated from 200–800?°C under 20?N and 30?N using a ball-on-disc tribometer. Characterization techniques included scanning electron microscope, X-ray diffraction, microhardness, porosity, and bond strength. WC-CoCr coating showed higher hardness and bond strength than Cr3C2-25%CoNiCrAlY. Both coatings exhibited reduced wear rates until 600?°C, after which the wear rates increased at 800?°C due to enhanced oxidation. The coefficient of Friction decreased with increasing temperature. At 600?°C, oxide phases helped reduce wear and friction. WC-CoCr coating shows better wear resistance than Cr3C2-25%CoNiCrAlY coating and the substrate. Wear mechanisms changed from abrasive and fatigue at 200?°C to oxidative and adhesive at 800?°C. Volumetric ball loss was higher for WC-CoCr due to its greater hardness. © The Author(s) 2025Item Effect of molybdenum on high-temperature tribological performance in HVOF sprayed of WC-based coatings on superni-76(SAGE Publications Ltd, 2025) Behera, N.; Sarmah, P.; Chandramouli, T.V.; Ramesh, M.R.This study examines the effects of Mo on the high-temperature wear and friction behavior of HVOF-sprayed 70%WC-Co/25%Mo/5%C and 70%WC-CrC-Ni/30%Mo coatings on Superni-76. The ball-on-disc tribometer wear tests were conducted at different temperatures (300°C and 600°C) and loads (10 and 30?N) against counter body Al2O3 ball. Microstructures and phase formation were investigated using SEM/EDS and XRD. The characterization of coating microhardness, surface roughness, and coating density was examined. The 70%WC-Co/25%Mo/5%C coating showed lower surface roughness and higher microhardness values than the 70%WC-CrC-Ni/30%Mo coating. The wear rate of the substrate increases with an increase in temperature, whereas 70%WC-Co/25%Mo/5%C and 70%WC-CrC-Ni/30%Mo coatings decrease with temperature from 300°C to 600°C. The coefficient of friction of substrate and coating decreases with increasing temperatures. The worn surfaces of 70%WC-Co/25%Mo/5%C and 70%WC-CrC-Ni/30%Mo coating contain oxide phases (WO3, Cr2O5) and lubrication phases (M0.2W0.8O3, CoMoO4, and MoO3) at 600°C. These oxide phases reduced the coating wear rate and coefficient of friction at 600°C. The 70%WC-Co/25%Mo/5%C coating showed improved resistance to wear and lower friction coefficient than the substrate and 70%WC-CrC-Ni/30%Mo coating. At temperatures of 300°C, the main abrasive wear mechanism changes to oxidative wear when the temperature reaches 600°C for both coatings. © The Author(s) 2025.Item Effect of wt% molybdenum content on the tribological properties of WC-10Ni/Mo coatings at elevated temperatures(Elsevier Inc., 2025) Behera, N.; Ravish, M.; Kumar, P.; Ramesh, M.R.Maraging Steel is widely used in automotive and aerospace components; however, it should not be exposed to high temperatures because of its poor wear and friction characteristics. This study investigates the effect of temperature on WC-10Ni coatings with the addition of molybdenum from 10 to 30 wt% applied on a Maraging Steel using a high-velocity oxy-fuel technique. A ball-on-disc tribometer with Al2O3 as a counterpart was used to evaluate the wear and friction properties of the coatings at RT, 300, and 600 °C and 10 and 30 N of load. The coating characterization was carried out using SEM, XRD, density measurements, microhardness testing, porosity evaluations, surface roughness measurements, and bond strength assessment. The wear rate and mechanism are ascertained using a 3D profilometer and SEM-EDS. The outcomes demonstrate that the WC-Ni/10 %Mo coating has greater bond strength and microhardness than the WC-Ni/20 %Mo and WC-Ni/30 %Mo coatings. The wear rate of the substrate increases with increasing temperature. The WC-Ni/20 %Mo and WC-Ni/30 %Mo coatings showed increasing wear rates until 300 °C, decreasing at 600 °C. At 600 °C, coatings included oxide phases such as NiWO4, WO3, MoO3, and NiMoO4, which helped lower the wear rate and coefficient of friction. Moreover, when temperatures rose, the coefficient of friction for all three coatings and substrates dropped. At all loads and temperatures, the WC-Ni/10 %Mo coating was well performed compared to WC-Ni/20 %Mo, WC-Ni/30 %Mo coating, and substrate regarding coefficient of friction and wear resistance. In particular, fatigue and abrasive wear predominated at RT, but oxidative, adhesive, and abrasive wear were all seen at 600 °C. The volumetric loss of the ball for WC-Ni/10 %Mo is higher than that of WC-Ni/20 %Mo and WC-Ni/30 %Mo coatings due to the higher hardness of WC-Ni/10 %Mo coating. © 2025Item Wear and frictional behaviour of partially oxidized and plasma sprayed NiCr and NiCrBSiFe coatings(Nature Research, 2025) Medabalimi, S.; Rokkala, U.; Gudala, S.; Behera, N.; Ramesh, M.R.; Dejene, M.The wear performance of partially oxidized NiCr and NiCrBSiFe coatings were investigated by varing load and speed. The partial oxidized powders were processed from the alloy powder using a flame spray process that involved spraying into distilled water. The partially oxidized powder was then plasma-sprayed onto MDN321 steel. The coatings were characterized for adhesive strength, microhardness, and density. The wear behavior was evaluated at disc speeds of 1, 2, and 3 m/s, with loads ranging from 10 to 50 N, over a 3000 m sliding distance. A significant difference in wear rates between the coating and substrate was observed. Operating at a sliding velocity of 1 m/s under a 10 N load, the substrate’s wear rate was found to be 3.56 times higher than that of the NiCrBSiFe coating, whereas for NiCr coating, it was 2.78 times higher. Wear rate coefficient performance shift takes place between the coatings at 12 N-m/s, product of applied load (C) and sliding velocity (V). In NiCrBSiFe coating, the wear mechanism observed at lower speeds and loads is micro-brittle and mechanism shifts to abrasive wear at higher speeds and loads. In the NiCr partially oxidized coating, the wear mechanism observed involves spallation of the coating at higher loads and adhesive wear at lower loads. Thermo gravimetric analysis of the coatings revealed a weight loss percentage of 1.42 for NiCrBSiFe and 14.09 for NiCr coatings. These findings highlight the NiCrBSiFe partially oxidized coating as being tenfold more stable at high temperatures compared to the NiCr partially oxidized coating. © The Author(s) 2025.