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    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, Hatem
    In 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.
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    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, Hatem
    In 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.
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    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.
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    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.
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    Ni/MWCNT Coatings Produced by Pulse Electrocodeposition Technique
    (Taylor & Francis Inc, 2015) Kartal, Muhammet; Gül, Harun; Uysal, Mehmet; Alp, A.; Akbulut, Hatem
    Nickel/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.
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    The Preparation of Zeolite/Ag Composite Powders by Electroless Deposition Process
    (Springer, 2014) Uysal, Mehmet; Karslıoğlu, Ramazan; Gül, Harun; Aslan, Serdar; Keskin, S.Y.; Okumuş, S.C.; Alp, A.
    Core-shell Ag-coated zeolite composite powders were synthesized using silver electroless deposition process, which was carried out in an ammonia-based coating solution containing silver nitrate as a precursor material. The influence of the chemical components and powder concentration in the Ag coating was investigated by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction techniques. The zeolite/Ag composite powders were fabricated in order to find an antibacterial material and a new implant material based on the microstructural change of zeolite/Ag composites powders using different parameters of Ag deposition.
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    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, Hatem
    Nickel-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.