Faculty Publications
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Item Characterization and Sliding Wear Behavior of Iron-Based Metallic Coating Deposited by HVOF Process on Low-Carbon Steel Substrate(Springer, 2020) Prasad, C.D.; Jerri, A.; Ramesh, M.R.The main aim of this work is to improve the sliding wear resistance of boiler steel material. The iron-based or Metco 41C metallic feedstock was deposited over the ASTM-SA213-T11 steel substrate using high-velocity oxy-fuel spraying process. The resultant deposits were subsequently characterized for microstructure, density, hardness, porosity and surface roughness. These characterizations were carried out with the help of XRD, SEM and Vickers’s microhardness tester. The sliding wear performance of the substrate and coatings were investigated by varying normal loads of 10 N and 20 N at temperatures of 200 °C, 300 °C as well as room conditions by employing pin-on-disk tribometer. The friction coefficient, volume of wear loss and wear rate were being found out. The wear results were compared among the substrate and coating. The formation of additional carbide phases such as Fe2C and SiC in Metco 41C coating led to higher hardness results in better wear resistance compared with the substrate. © 2020, Springer Nature Switzerland AG.Item EFFECT of LASER POST-TREATMENT on MICROSTRUCTURAL and SLIDING WEAR BEHAVIOR of HVOF-SPRAYED NiCrC and NiCrSi COATINGS(World Scientific, 2022) Naik, T.; Mathapati, M.; Prasad, C.D.; Nithin, H.S.; Ramesh, M.R.In this study, NiCrC and NiCrSi coatings are deposited on the MDN 310 steel using High-Velocity Oxy-Fuel (HVOF) process. Laser Surface Melting (LSM) post-heat treatment is carried out on as-sprayed coatings using Laser Engineered Net Shaping (LENSTM) with a power of 300W. The characteristics of both coatings in terms of mechanical and metallurgical properties have been investigated. The thicknesses of the as-sprayed NiCrC and NiCrSi coatings are in the range of 170-200μm. Laser-treated NiCrC and NiCrSi coatings exhibit a thickness range of 162-185μm, respectively. The microstructure of laser-treated NiCrC-300W coating clearly shows a dendrite-like structure, whereas the laser-treated NiCrSi coating exhibits hard layer and columnar homogeneity. Microhardness of as-sprayed NiCrC coating is 515±15 HV0.3 and that of NiCrSi coating is 645±25 HV0.3. Microhardness of laser-treated NiCrC coating is 720±30 HV0.3 and that of NiCrSi coating is 890±15 HV0.3. Dry sliding wear tests are conducted at room temperature (RT) and 400°C with 10-N and 20-N loads. The wear rates at 400°C temperature of laser-treated NiCrC and NiCrSi coatings produced are slightly below (1-2.2)×10-3mm3/m and (0.8-1.6)×10-3mm3/m, respectively. Laser-treated coatings produced better dry sliding wear behavior compared with as-sprayed coatings owing to dense microstructure. Formation of SiC phase in NiCrSi coating imparts high wear and frictional resistance compared to the NiCrC coating. © 2022 World Scientific Publishing Company.Item Effect of Mo- and SiC-Reinforced NiCr Microwave Cladding on Microstructure, Mechanical and Wear Properties(Springer, 2023) Sharanabasava, H.; Prasad, C.D.; Ramesh, M.R.A microwave hybrid heating technique was applied to produce the NiCr-Mo-SiC composite cladding on Titan-31. The developed claddings were tested for microstructural features, phase analysis, microhardness, and surface roughness parameters using scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers Microhardness, and 3D optical profilometers, respectively. Using a static alumina indenter on microwave clads, the linear reciprocator ball on plate wear test was performed. Both friction and wear track metrics have been studied. A dense microstructure without observable holes or fractures has been achieved, together with a homogeneous distribution of hard phases and strong metallurgical bonding. Cladding is typically three times tougher than the underlying metal. Due to the formation of hard carbide phases, which increased hardness and internal lubricity, cladding has a lower coefficient of friction than the substrate. © 2023, The Institution of Engineers (India).Item Characterization and Wear Behavior of NiCrMoSiC Microwave Cladding(Springer, 2024) Sharanabasava, H.; Prasad, C.D.; Ramesh, M.R.A microwave hybrid heating technique has been employed to develop NiCr-Mo-SiC composite cladding on titanium alloy (Grade-5/Ti-6Al-4 V/Titan-31). The developed claddings have been characterized for microstructural features, phase analysis, microhardness measurements, and 3D optical profile parameters by employing scanning electron microscopy, x-ray diffraction, Vickers microhardness tester, and 3D optical profilometer, respectively. Microwave clads have been subjected to linear reciprocator ball on plate wear test with static alumina indenter. Wear track parameters and friction coefficients have been studied. A dense microstructure with uniform distribution of hard phases and good metallurgical bonding with no visible pores and cracks has been obtained. Cladding exhibits nearly 2 times higher hardness than the base alloy. Coefficient of friction studies revealed that higher molybdenum content enhances internal lubricity. © 2023, ASM International.