Department of Mechanical engineering
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Item Prediction and optimization of microhardness and corrosion behaviour of CuNi-Gr composite coatings(University of Politennica, 2024) Belgamwar, Sachin U.; Rathore, Jitendra S.Graphene nanoplatelets (Gr) as fillers for alloy composite coatings has increased due to their remarkable high aspect ratio and distinctive plate-like structure. Piping, condensers and heat exchangers in seawater systems, desalination plants, marine hardware and boat hulls are expected to exhibit high wear and corrosion resistance. For this purpose, CuNi-Gr composite coatings have been fabricated using electrodeposition technique and investigated their microhardness and anti-corrosion properties. During the electrodeposition of coatings, the various process variables such as pH, current density, Gr concentration and amount of nickel sulfate have been taken into account. To achieve the full potential of CuNi-Gr composite coating in engineering applications, this study optimizes the performance of the CuNi-Gr composite coating using an orthogonal array design of a Taguchi technique. By Taguchi and regression analysis, it was found that the Gr concentration in the electrolyte is the most influencing parameter of the process for microhardness and polarization resistance of the CuNi-Gr composite coatings. It has been observed that the microhardness and polarization resistance of the composite coatings increase with the increase in the Gr content up to 400 mg/L.Item Sustainability in magnetic metal-carbon nanocomposites: a comprehensive review of manufacturing, characterization, and applications(EDP Sciences, 2024-07) Belgamwar, Sachin U.Magnetic metal-carbon nanocomposites (MMCN) are emerging as sustainable materials, consisting of magnetic metals or alloys and carbon-based materials like CNT, graphene (Gr), carbon fiber (CF), and activated carbon. These materials possess unique magnetic properties that depend on various factors, such as preparation conditions, metal content, and phase composition. Incorporating carbon-based materials into magnetic metals has been observed to enhance their magnetic properties, including magnetic strength and moment. Researchers employ a range of tests to characterize these materials, such as FTIR, XRD, FESEM, TEM, BET, and VSM. Carbon-based materials such as CNT, graphene, etc., have been used as filler materials to reinforce the metal matrix because of their sustainability, tendency to integrate, and low cost. Further, they enhance the tribological performance and mechanical strength, provide corrosion resistance and improve electrical and thermal properties. Additionally, the addition of filler magnetic material in single or hybrid form into the carbon matrix increases the scope of application of MMCN. These composites are widely used in the application of biomedical, semiconductors, tribology, fuel cells, etc. In the present study, a comprehensive review has been carried out to provide a view of the fabrication aspect of the MMNC and to understand the role of the reinforcement method used to fabricate the composites. Finally, it covers different uses of the MMCN, which can lead to an eco-friendly environment.Item An experimental investigation on the pool boiling heat transfer of R-134A on microporous cu-mwcnt composite surfaces(MDPI, 2024-01) Belgamwar, Sachin U.Multiwalled carbon nanotubes (MWCNTs) exhibit outstanding physical properties, including high thermal conductivity, excellent mechanical strength, and low electrical resistivity, which make them suitable candidates for a variety of applications. The work presented in this paper focuses on the pool boiling performance of refrigerant R-134a on microporous Cu-MWCNT composite surface layers. A two-stage electrodeposition technique was used to fabricate Cu-MWCNT composite coatings. In order to achieve variation in the surface properties of the Cu-MWCNT composite surface layer, electrodeposition was carried out at various bath temperatures (25 °C, 30 °C, 35 °C, and 40 °C). All surfaces coated with the Cu-MWCNT composite demonstrated superior boiling performance compared to the uncoated surface. Heat transfer coefficient (HTC) values for Cu-MWCNT composite surface layers, prepared at bath temperatures of 25 °C, 30 °C, 35 °C, and 40 °C, exhibited improvements of up to 1.75, 1.88, 2.06, and 2.22, respectively, in comparison to the plain Cu surface.Item Role of reinforcement on the tribological properties of polytetrafluoroethylene composites: A comprehensive review(Wiley, 2024-07) Belgamwar, Sachin U.Polytetrafluoroethylene (PTFE) is widely used in tribological applications. However, it faces challenges due to its high wear rate. Reinforcement of additives in PTFE reduces its wear rate by up to 10,000 times in dry conditions. Infusing metallic filler materials like Al, Cu, and Pb improves PTFE wear performance but increases the coefficient of friction (COF). However, it may not be suitable for corrosive environments due to potential metal reactivity. Reinforcing PTFE composites with carbon-based materials reduces weight, improves wear properties, and lowers COF. Pre-treated materials enhance bonding for improved anti-friction and anti-wear properties. PTFE and its composites are widely used in journal bearings, bearing pads, and ball bearings due to their excellent low-speed, low-load lubrication properties. They outperform Babbitt alloy in bearing pads, except in heat conductivity. PTFE can also be used as a solid lubricant and can be combined with additives for improved performance. Apart from it, achieving an optimal combination of properties for all forms of reinforcement can be challenging due to the difficulty in determining exact values for multiple properties with specific types of reinforcement. This article provides a comprehensive review that delves into the significant findings pertaining to reinforcement and its application in bearing technology.Item Tribological characterization of PTFE composites for ball bearing applications(Taylor & Francis, 2024-11) Belgamwar, Sachin U.Polymer-based ball bearings have emerged as a replacement for metal-based bearings in certain applications. They have recently gained attention due to their low weight-to-strength ratio, self-lubrication properties, and noncorrosive nature. The purpose of this article is to present the use of polytetrafluoroethylene (PTFE) in ball-bearing applications. In this study, five types of PTFE composites were selected, and their detailed tribological characterizations were performed based on the testing parameters of a polymer ball bearing with a bore diameter of 20 mm. Tribological characterization was performed using a pin-on-disc, in which the pin was sliding against the steel counterpart. The test pin was subjected to 100 to 150 N loads with 25 N steps at 1000,1200 and 1500 RPM. Further, wear analysis of the composites was performed using SEM and AFM, and the transfer of the film on the counterpart was analyzed using an optical microscope. The findings revealed that the 25% carbon-filled, 40% bronze-filled, and 15% PEEK-filled PTFE composites were suitable for ball-bearing applications for the defined load and speed. Pure PTFE and 25% glass fiber-filled didn’t yield favorable results owing to the high wear rate.Item Experimental investigation of pool boiling heat transfer on CU─AI2O3 composite coated patterned surfaces using refrigerant R-134A(Wiley, 2024-11) Belgamwar, Sachin U.The present study investigates pool boiling heat transfer (PBHT) of R-134a on Cu─Al2O3 composite-coated patterned surfaces (CPSI, CPSII, CPSIII, and CPSIV). Using a wire EDM method, four different types of copper patterned surfaces (PSI, PSII, PSIII, and PSIV) were manufactured. Comparing the heat transfer coefficients (HTCs) of the Cu─Al2O3 composite-coated patterned surfaces to the uncoated Cu surfaces, a notable enhancement was observed. The maximum HTC improvements of 162%, 178%, 189%, and 211% were observed for CPSI, CPSII, CPSIII, and CPSIV, respectively, when compared with bare Cu surfaces. These results demonstrate the effectiveness of these treatments in enhancing heat transfer compared to bare copper surfaces. The enhancement in PBHT is mainly due to the integration of porous Cu─Al2O3 composite coating with patterned surfaces which resulted in a larger heat transfer area, improved capillary action, and a substantial increase in active nucleation sites.Item Assessment of polytetrafluoroethylene composites for deep groove ball bearing applications through free run and rolling contact fatigue tests(Springer Nature, 2025-03) Belgamwar, Sachin U.Polytetrafluoroethylene (PTFE) is widely used in tribological applications. However, its usage in the ball-bearing application has not been explored. The present study investigates the usage of PTFE composites for deep groove ball (DGB) bearings. Initially, a ball-on-disc experiment is conducted to analyze the interaction between pure PTFE, 40% bronze-filled, 25% glass fiber-filled PTFE composites, and Si3N4 balls by determining the coefficient of friction (COF) and specific wear rate. Then, the reliability of the fabricated DGB is checked through free run and rolling contact fatigue (RCF) tests using a 6-channel DAQ system (OR35-INST). In the free run test, a rotor supported on fabricated polymer bearing sets is rotated up to two million cycles under minimal load conditions. Its vibrational signals and RPM are continuously monitored through an accelerometer and tachometer. After a subsequent number of cycles, the dynamic characteristics of the shaft are recorded using the DAQ system and eddy probes. Finally, an RCF test is conducted to check the load-bearing capacity of the bearing. The bearing is subjected to a 36 N to 108 N (in step of 36 N) load, and the vibration signals are recorded.Item PTFE/carbon composite radial deep groove ball bearings: Part 1–tribological characterization suitable for ball bearing applications(Sage, 2025-05) Belgamwar, Sachin U.Polytetrafluoroethylene (PTFE) is a self-lubricating, highly stable, high-performing polymer that has expanded its usage in bearing tribology. However, its application in ball bearings is still limited. This article explores using PTFE/carbon composites to evaluate their suitability for radial deep groove ball-bearing applications. The proposed work is divided into two parts. The first part focuses on the tribological characterization of the PTFE/carbon through a ball-on-disc test and examines the effect of reinforcement on bearing performance. The second part focuses on fabricating and analysing PTFE/carbon radial deep groove ball bearings for characteristics. In the first part, a ball-on-disc experiment was performed on pure PTFE (PTFE) and 25% carbon-filled PTFE (CR25) to measure the coefficient of friction (COF) and wear rate. These materials were subjected to three loading conditions at a particular speed using silicon nitride balls (Si3N4). The friction coefficient was recorded throughout the interaction, and specific wear rates were calculated. After completing the tests, wear tracks were analyzed using a scanning electron microscope and a Contracer.Item Pool boiling heat transfer enhancement on micro- and nano-structured copper surface(Springer, 2025-04) Belgamwar, Sachin U.As the power requirements of industrial and electronic equipment continue to increase, thermal management is becoming more and more important. BHT, or pool boiling heat transfer, is acknowledged as an effective technique for handling large heat loads. In this study, experimental work on pool BHT is conducted on a surface coated with porous Cu and R-141b. The porous coating is achieved using two-stage electrodeposition techniques on a plain Cu surface. Characterization results reveal that the copper coating consists of a combination of nano- and microporous structures. Experimental studies have shown that the presence of a Cu-coated surface significantly enhances the Heat Transfer Coefficient (HTC) by up to 53% compared to a surface coated only with Cu. Additionally, the Cu-coated surface reduces heat compared to the uncoated surface. These findings demonstrate that the porous Cu coating surface can effectively increase surface area, cavitation, and nucleation density, which are beneficial for heat transfer applications.Item Critical review of reinforcement effect in peek tribology and its usage in biomedical, coating and bearing applications(Taylor & Francis, 2025-01) Belgamwar, Sachin U.Polyetheretherketone (PEEK) is an ultra-high-performance polymer renowned for its excellent wear resistance, making it widely used in tribological applications. However, its high coefficient of friction (COF) can detract from its performance. Reinforcing appropriate filler materials can significantly enhance its tribological properties, making it suitable for biomedical, coatings, and bearing applications. The review’s focus is to provide a detailed understanding of the role of reinforcement in affecting the PEEK tribology, covering different forms of reinforcement from fiber to nanofiller in single or hybrid forms. Moreover, the article develops into the testing conditions that can influence its performance, which include material modification, environmental conditions, lubrication state and testing parameters like load, velocity, etc. Further, an in-depth discussion is provided about the role of reinforcement in PEEK usage in biomedical, bearing and coating applications. This article’s effort provides the researchers with scientific knowledge of the reinforcement role in PEEK tribology and major application usage. Further, it offers different areas where there is scope for improvement.