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Öğe Effect of CTAB concentration in the electrolyte on the tribological properties of nanoparticle SiC reinforced Ni metal matrix composite (MMC) coatings produced by electrodeposition(Elsevier, 2013) Kılıç, Fatih; Gül, Harun; Aslan, Serdar; Alp, A.; Akbulut, HatemIn this study, a nickel sulfate bath containing SiC nanoparticles (between 100 and 1000 nm) was used to obtain hard and wear-resistant nanoparticle reinforced Ni-SiC MMCs on steel surfaces for anti-wear applications, such as dies, tools and working parts. The influence of stirring speed and surfactant concentration on particle distribution, microhardness and wear resistance of nano-composite coatings has been studied. The nickel films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The depositions were controlled to obtain a specific thickness (between 50 and 200 mu m) and particle volume fraction in the matrix (between 0.02 and 0.12). The hardness of the resulting coatings was also measured and found to be 280-571 Hv, depending on the particle volume in the Ni matrix. The effects of the surfactant on the zeta potential, co-deposition and distribution of SiC particles in the nickel matrix, as well as the tribological properties of composite coatings, were investigated. The tribological behaviors of the electrodeposited SiC nano composite coatings sliding against M50 steel ball (empty set 10 mm) were examined on a CSM Instrument. All friction and wear tests were performed without lubrication at room temperature and in the ambient air (relative humidity 55-65 %). The results showed that the wear resistance of the nano composites was approximately 2-2.2 times higher than unreinforced Ni deposited material. (c) 2012 Elsevier B.V. All rights reserved.Öğe Effect of particle concentration on the structure and tribological properties of submicron particle SiC reinforced Ni metal matrix composite (MMC) coatings produced by electrodeposition(Elsevier Science Bv, 2012) Gül, Harun; Kılıç, Fatih; Uysal, Mehmet; Aslan, Serdar; Alp, A.; Akbulut, HatemIn the present work, a nickel sulfate bath containing SiC submicron particles between 100 and 1000 nm was used as the plating electrolyte. The aim of this work is to obtain Ni-SiC metal matrix composites (MMCs) reinforced with submicron particles on steel surfaces with high hardness and wear resistance for using in anti-wear applications such as dies, tools and working parts for automobiles and vehicles. The influence of the SiC content in the electrolyte on particle distribution, microhardness and wear resistance of nano-composite coatings was studied. During the electroplating process, the proper stirring speed was also determined for sub-micron SiC deposition with Ni matrix. The Ni films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The depositions were controlled to obtain a specific thickness (between 50 and 200 mu m) and volume fraction of the particles in the matrix (between 0.02 and 0.10). The hardness of the coatings was measured to be 280-571 HV depending on the particle volume in the Ni matrix. The tribological behaviors of the electrodeposited SiC nanocomposite coatings sliding against an M50 steel ball (empty set 10 mm) were examined on a tribometer. All the friction and wear tests were performed without lubrication at room temperature and in the ambient air (with a relative humidity of 55-65%). The results showed that the wear resistance of the nanocomposites was approximately 2-2.2 times more than those of unreinforced Ni. (C) 2011 Elsevier B.V. All rights reserved.Öğe Effect of PC electrodeposition on the structure and tribological behavior of Ni-Al2O3 nanocomposite coatings(Elsevier Science Sa, 2014) Gül, Harun; Uysal, Mehmet; Akbulut, Hatem; Alp, AhmetIn this study, Ni-Al2O3 metal matrix composite (MMC) coatings were prepared from a modified Watt's type electrolyte by pulse current (PC) plating under current densities varying between 1 and 9 A/dm(2). The tribological tests were performed with a reciprocating ball-on-disk apparatus sliding against a M50 steel ball (empty set 10 mm). The wear tests were carried out at sliding velocities of 50, 100 and 150 mm/s under a constant load. The results compared with our previously published work of DC electrodeposited coatings. The results showed that the electrodeposition method can significantly affect the microstructure and tribological behavior of Ni-Al2O3 nanocomposite coatings. For the same current density, PC electrodeposition creates coatings with higher co-deposited particle content more homogenous particle distribution, higher wear resistance at high sliding distance and improved friction coefficients. The superior dispersion of Al2O3 nanoparticles in PC-coated materials contributed to its increased load bearing capacity. Detailed tribological tests and characterization showed that DC- and PC-coated nanocomposite layers yielded different wear mechanisms depending on the sliding velocity. (C) 2014 Elsevier B.V. All rights reserved.Öğe Effect of reciprocating sliding speed on the tribological performance of nano Al2O3 reinforced Ni MMCs produced by DC and pulse electro co-depositions(European Conference on Composite Materials, ECCM, 2012) Gül, Harun; Akbulut, Hatem; Alp, A.In this study, Ni/Al2O3 metal matrix composite (MMC) coatings were prepared from a modified Watt's type electrolyte by direct and pulse current (DC and PC) plating methods, and the effect of current density is investigated. The tribological tests were performed by a reciprocating ball-on disk apparatus sliding against M50 steel ball (Ø 10 mm). The wear tests were carried out at different sliding velocities of 50 mm/s, 100 mm/s and 150 mm/s by using a constant load. Increasing sliding velocity resulted in increasing wear rate in DC produced coatings but decreasing in PC co deposited materials.Öğe Effect of reciprocating sliding speed on the tribological performance of nano SiCp reinforced Ni-metal matrix composites produced by electrocodeposition(2012) Gül, Harun; Akbulut, Hatem; Aslan, Serdar; Alp, A.In the present work, Ni/SiC metal matrix composite (MMC) coatings were prepared from a modified Watt's type electrolyte containing nano-SiC particles by direct current (DC) plating method to increase wear resistance of the electro co-deposited Ni. SiC nano particles with average particle size of 0, 1-1 ?m were co-deposited with nickel matrix on the steel substrates. For this purpose, several studies were carried out to optimize deposition parameters for specific applications. The depositions were controlled to obtain the specific thickness (between 175-200 ?m) and particle volume fraction in the matrix (between 0.03 and 0.10). The hardness of the resultant coatings was measured and found to be 280-571 HV depending on the particle concentration in the electrolyte and therefore, particle volume in the Ni matrix. The tribological tests were performed by a reciprocating ball-on disk apparatus sliding against M50 steel ball (ø10 mm). All the friction and wear tests were performed under the unlubricated conditions at room temperature and in the ambient air (relative humidity 55-65%). The wear tests were carried out at different sliding velocities of 50 mm/s, 100 mm/s and 150 mm/s by using a constant dead load of 1.0 N. It was detected that increasing sliding speed resulted to increase wear rate but decreasing friction coefficient due to change in wear mechanism. Increasing sliding speed showed formation of tribo induced oxides up to 20 g/l SiCp in the electrolyte and wear mechanism was controlled by temperature induced fatigue wear. Further increase in the SiCp in the electrolyte caused an abrasive type of the wear. Copyright © 2012 American Scientific Publishers All rights reserved.Öğe Effect of surfactant concentration in the electrolyte on the tribological properties of nickel-tungsten carbide composite coatings produced by pulse electro co-deposition(Elsevier Science Bv, 2015) Kartal, Muhammet; Uysal, Mehmet; Gül, Harun; Alp, Ahmet; Akbulut, HatemA nickel plating bath containing WC particles was used to obtain hard and wear-resistant particle reinforced Ni/WC MMCs on steel surfaces for anti-wear applications. Copper substrates were used for electro co-deposition of Ni matrix/WC with the particle size of <1 mu m tungsten carbide reinforcements. The influence of surfactant (sodium dodecyl sulfate, SDS) concentration on particle distribution, microhardness and wear resistance of composite coatings has been studied. The nickel films were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of the surfactant on the zeta potential, co-deposition and distribution of WC particles in the nickel matrix, as well as the tribological properties of composite coatings were also investigated. The tribological behaviors of the electrodeposited WC composite coatings sliding against M50 steel ball (empty set 10 mm) were examined on a CSM Instrument. All friction and wear tests were performed without lubrication at room temperature and in the ambient air (relative humidity 55-65%). (C) 2015 Elsevier B.V. All rights reserved.Öğe Graphene aerogel-supported Na3V2(PO4)3/C cathodes for sodium-ion batteries(Elsevier Science Sa, 2023) Gultekin, Sidika Yildirim; Guler, Aslihan; Kuruahmet, Deniz; Gungor, Hatice; Singil, Mustafa Mahmut; Uzun, Esma; Akbulut, HatemNa3V2(PO4)3 (NVP) is a preferred cathode material for Na-ion batteries due to its good thermal stability and long cycle life, but its low electrical conductivity limits its use. The carbon coating method is widely available in the literature but can solve the problem to a limited extent. Graphene aerogel-based composite materials with lightweight, high surface area and 3-dimensional (3D) porous structure are prepared, and the properties are tried to be improved further. In this study, carbon-coated Na3V2(PO4)3 (NVP/C) and graphene aerogel-carbon-coated Na3V2(PO4)3 (GA-NVP/C) composite have been synthesized. The produced samples have been analyzed using Field emission scanning electron microscopy, X-ray diffraction, Raman spectrum, Thermal Gravity Analysis, Xray photoelectron spectroscopy, Brunauer-Emmett-Teller and Transmission electron microscopy. Then, the effect of graphene aerogel additive on electrochemical performances as cathode materials has been investigated. Even though GA-NVP/C and NVP/C have similar discharge capacities in the first cycle, GA-NVP/C shows high cycle stability when compared to NVP/C after 250 cycles. The GA-NVP/C cathode also has a higher discharge capacity than the NVP/C cathode at different current rates. The diffusion coefficient calculated using the cyclic voltammetry curve of GA-NVP/C is also high, supporting the graphene aerogel's positive results. In conclusion, we show that adding GA with a 3-dimensional porous structure greatly improves the electrochemical properties of the cathode in Na-ion batteries.Öğe Ni/MWCNT Coatings Produced by Pulse Electrocodeposition Technique(Taylor & Francis Inc, 2015) Kartal, Muhammet; Gül, Harun; Uysal, Mehmet; Alp, A.; Akbulut, HatemNickel/multiwalled carbon nanotube (MWCNT) metal matrix composite coatings were deposited by pulse electrocodeposition method from a Watt's-type electrolyte. The influence of the MWCNT content in the electrolyte on the particle codeposition and distribution, the surface morphology, microstructure, microhardness of nanocomposite coatings were studied. Copper substrates were used for electrocodeposition of Ni matrix/MWCNTs with the diameter of 50-60 nm and length of 10-mu m carbon nanotube reinforcements. The electrodeposited Ni matrix coatings were characterized by scanning electron microscopy and X-ray diffraction analysis.Öğe Preparation and characterization of bronze/SiCp composites produced via current activated sintering method(Elsevier Sci Ltd, 2015) Gül, Harun; Uysal, Mehmet; Alp, Ahmet; Akbulut, HatemIn this study, bronze matrix was reinforced with nickel coated nano SiC particles using mechanical alloying and then subsequent rapid current sintering technique. Mechanical ball milling of bronze matrix composite powders were performed with 1.0, 3.0 and 5.0 vol% SiC nanoparticle reinforcements. The composite powders were cold compacted under constant pressure of 150 MPa. The compacted structures were sintered at atmospheric conditions almost to the full density within 10 min using current sintering, in which the powders were heated by a low voltage and high amperage current and compressed simultaneously to achieve dispersion of nano SIC particles. The samples were sintered at 900 A current to eliminate porosities and agglomeration of particles. The porosity of the produced samples were reduced from 9.49% to 6.13% respectively for the uncoated and coated 5.0 vol% SiC reinforced nanocomposites. Microhardness testing and scanning electron microscopy (SEM) were used for the microstructural characterization of the composites. Rapid sintering was also thought to be an advantage to eliminate volume increment seen under conventional atmospheric sintering conditions. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Preparation and Characterization of Copper Powders with Sn Coating by the Electroless Plating(Polish Acad Sciences Inst Physics, 2015) Uysal, Mehmet; Çetinkaya, Tuğrul; Gül, Harun; Kartal, Muhammet; Algül, Hasan; Tokur, Mahmud; Akbulut, HatemIn this work, Sn-Cu composite powders were produced using an electroless process. The tin content on the surface of copper powders was vaned by using different concentrations of SnSO4 in the plating bath. The surface morphology of the produced Sn-Cu composite powders was characterized using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) was used to determine the elemental surface composition of the composites. X-ray diffraction (XRD) analysis was performed to investigate the structure of the Sn-Cu composite powders. The electrochemical performance of Sn-Cu nanocomposites was studied by charge/discharge tests.Öğe Preparation of Sn-Co alloy electrode for lithium ion batteries by pulse electrodeposition(Pergamon-Elsevier Science Ltd, 2014) Gül, Harun; Uysal, Mehmet; Çetinkaya, Tuğrul; Güler, Mehmet Oğuz; Alp, Ahmet; Akbulut, HatemSn-Co alloy films for Li-ion batteries were prepared by pulse electrodeposition on the copper foils as current collectors. Nanocrystalline Sn-Co alloy electrodes produced by using a solution containing cobalt chloride and tin chloride at constant electrodeposition conditions (pulse on-time too at 5 ms and pulse off-time toff at 5 ms) with varying peak current densities, Jp have been investigated. The structures of the electroplated Sn-Co alloy thin films were studied to reveal film morphology current density relationships and the effect of the current density parameters on the electrochemical properties. X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analyzer and Energy-Dispersive X-ray Spectroscopy (EDS) facilities were used for determination the relationships between structure and experimental parameters. Cyclic voltammetry (CV) tests were carried out to reveal reversible reactions between cobalt tin and lithium. Galvanostatic charge/discharge (GC) measurements were performed in the cells formed by using anode composite materials produced by pulse elect co-deposition. The discharge capacities of these cells were cyclically tested by a battery tester at a constant current in the different voltage ranges between 0.02 V-1.5 V. The results have shown that Sn-Co alloy yielded promising reversible discharge capacities with a satisfactory cycle life for an alternative anode material to apply for the Li-ion batteries. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe Pulse electrocodeposition of Ni/MWCNT nanocomposite coatings(Taylor & Francis Ltd, 2015) Kartal, Muhammet; Uysal, Mehmet; Gül, Harun; Alp, Ahmet; Akbulut, HatemNickel/multiwalled carbon nanotube (MWCNT) metal matrix composite coatings were deposited by pulse electrocodeposition method from a Watt's type electrolyte. The influence of peak current density on the particle codeposition and distribution, the surface morphology, microstructure, microhardness and wear resistance of nanocomposite coatings were studied. Copper substrates were used for electrocodeposition and MWCNTs with the diameter of 50-60 nm and length of 10 mm used as reinforcements. The electrodeposited Ni matrix coatings were characterised by scanning electron microscopy, Raman spectroscopy and X-ray diffraction analysis.Öğe Reciprocating sliding speed effect on the tribological properties of SiCp reinforced Ni MMCs deposited by electroplating(European Conference on Composite Materials, ECCM, 2012) Gül, Harun; Aslan, Serdar; Akbulut, Hatem; Alp, AhmetIn the present work, Ni/SiC metal matrix composite (MMC) coatings were prepared from a modified Watt's type electrolyte containing nano-SiC particles by direct current (DC) plating method to increase wear resistance of Ni. The influence of surfactant content on co-deposition of SiC particles (0.1-1.0 ?m size range) in the matrix, and tribological properties were investigated. The influence of sliding speed on the tribological performances of the coatings was investigated by a reciprocating ball-on disk apparatus. The wear tests were carried out at different sliding speeds by using a constant load. Wear resistances and friction coefficients of Ni/SiC composites were decreased by increasing sliding speed because of temperature-controlled surface oxidation. The change in wear mechanisms by changing surfactant content and sliding speeds were also comprehensively studied and, in general, decreasing surface damage was obtained by increasing sliding speed.Öğe A reciprocating wear study on the effect of surfactant concentration and sliding speed in the electro codeposited Ni/SiCp metal matrix composites(Sage Publications Ltd, 2016) Gül, Harun; Uysal, Mehmet; Akbulut, Hatem; Alp, AhmetIn this present work, Ni/SiC metal matrix composite coatings were prepared from a modified Watt's type electrolyte containing nano-SiC suspended particles by direct current plating method to increase the wear resistance of Ni. The influence of surfactant content on codeposition of SiC particles within the matrix and tribological properties were investigated. A wide particle size range (between 0.1 and 1.0 mu m) was chosen to provide a high load bearing ability for the codeposited layers. The wear tests were carried out at different sliding speeds by using a constant load. The influence of sliding speed on the tribological performances of the coatings has been investigated by using a reciprocating ball-on disk apparatus. Wear resistances and friction coefficients of Ni/SiC composites were decreased by increasing sliding speed due to temperature-controlled surface oxidation. The change in wear mechanisms by changing surfactant content and sliding speeds were also comprehensively studied.Öğe Sn-Ni/MWCNT nanocomposite negative electrodes for Li-ion batteries: The effect of Sn:Ni molar ratio(Pergamon-Elsevier Science Ltd, 2014) Uysal, Mehmet; Gül, Harun; Alp, Ahmet; Akbulut, HatemSince Ni is used to behave as a buffer component in the Sn-based anode materials for the Li-ion batteries, it is aimed to reveal the optimum Sn:Ni ratio to reduce the electrode pulverization emanated from volume increase during the charge/discharge process. MWCNTs were also co-deposited from the suspended MWCNT in the electrolyte to increase buffering effect and conductivity. To reduce irreversible capacity and improve cycle performance of tin electrodes, Sn-Ni/MWCNT three components nanocomposite electrodes were prepared with different Sn:Ni ratio by pulse electrodeposition method using copper substrate as current collector. The morphology and the structures of the Sn-Ni/MWCNT nanocomposites were characterized by scanning electron microscopy (SEM), Xray diffraction (ICED). Raman spectroscopy was used to determine the existence of MWCNT in the Sn-Ni matrix. The electrochemical performance of Sn-Ni/MWNT nanocomposites studied by charge/discharge tests and cyclic voltammetry experiments. Results showed that increasing the amount of co-deposited Ni has a strong effect on the electrochemical performances. The best electrochemical results were obtained in the nanocomposite electrodes with Ni content of 29 wt.% Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe Tribological behavior of copper/MWCNT nanocomposites produced by pulse Electrodeposition(2014) Gül, Harun; Uysal, Mehmet; Akbulut, Hatem; Alp, AhmetCopper coatings containing well-distributed multiwalled carbon nanotubes were obtained by pulse electrodeposition in acidic sulfate bath in order to improve the microhardness and wear resistance of coatings. Multiwalled carbon nanotubes concentration was determined as the most significant factor for the incorporation of multiwalled carbon nanotubes in copper based electrolyte. The amount of embedded multiwalled carbon nanotubes and the microhardness of nanocomposites were found to increase with the increase of multiwalled carbon nanotubes in the electrolyte. The tribological properties of nanocomposites deposited by pulse electrocodeposition technique were studied by reciprocating ball on-disk method. The characterization of the coatings was investigated by scanning electron microscopy and X-ray diffraction facilities. The experimental results indicated that the wear resistance of copper composite is superior to that of pure copper. The friction coeffcient and wear rates decreased with the increase in the concentration of multiwalled carbon nanotubes in the electrolyte.Öğe Tribological Properties of TiO2 Reinforced Nickel Based MMCs Produced by Pulse Electrodeposition Technique(Springer India, 2015) Algül, Hasan; Gül, Harun; Uysal, Mehmet; Alp, A.; Akbulut, HatemNickel-TiO2 composite coatings were prepared under pulse current conditions by co-deposition of TiO2 particles and nickel from a Watts type bath. The effect of TiO2 particle concentration was studied on microhardness, friction coefficient and wear resistance. The morphological features and the structures were studied by scanning electron microscope, X-ray diffraction analysis and 3D profilometry facilities. A wide particle size range (between 95 and 140 nm) was chosen to provide a high dispersion and load bearing ability for the co-deposited layers. It was determined that increasing the particle concentration in the electrolyte dramatically increased the co-deposited TiO2 particles in the coating. The results showed that the high concentration of TiO2 particles in the electrolyte yielded the highest amount of particles co-deposited in the plating layer. The influence of the co-deposited TiO2 volume on microstructure and tribological properties in the coating were investigated. The wear tests were carried out using a constant load by a reciprocating ball-on disk configuration. Wear loss and friction coefficients of Ni/TiO2 composites were decreased by increasing TiO2 content in the electrolyte because of the increasing content of TiO2 in the deposited layer. The change in wear mechanisms by changing TiO2 content was also determined.
