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Öğe Alloying effect on K shell X-ray fluorescence parameters and radiative Auger ratios of Co and Zn in ZnxCo1-x alloys(Elsevier Science Bv, 2010) Aylikci, N. Kup; Tirasoglu, E.; Karahan, I. H.; Aylikci, V.; Cengiz, E.; Apaydin, G.In this study, sigma K-alpha,K-beta production cross-sections, omega(K) fluorescence yields, K-beta/K-alpha, KLM/K-alpha and KMM/K-beta intensity ratios of Co and Zn in different alloy compositions were measured. The alloying effects on the fluorescence parameters of Co and Zn were investigated. The changes in these parameters were interpreted according to the rearrangement of valance state electrons and the charge transfer process between the 3d elements which constitute the alloys. The samples were excited by 59.5 keV gamma-rays from a Am-241 annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. (C) 2009 Elsevier B.V. All rights reserved.Öğe Alloying effect on K X-ray intensity ratio and production cross section values of Zn and Cr in Zn-Cr alloys(Pergamon-Elsevier Science Ltd, 2013) Dogan, M.; Tirasoglu, E.; Karahan, I. H.; Aylikci, N. Kup; Aylikci, V.; Kahoul, A.; Cetinkara, H. A.In this study, sigma(K alpha), sigma(K beta) production cross-sections and K-beta/K-alpha intensity ratios of Cr and Zn have been measured in pure metals and in different alloy compositions which have different composition values. And also, empirical and semi-empirical K-shell fluorescence yields (omega(K)) and K-beta/K-alpha intensity ratios from the available experimental data for elements with 23 <= Z <= 30 were calculated. The experimental data are fitted using the quantity (omega(K)/(1-omega(K)))(1/4) vs. Z to deduce the empirical K-shell fluorescence yields and K-beta/K-alpha intensity ratios. The effects of alloying on the fluorescence parameters and bath temperatures on alloy compositions were investigated. Our analysis indicates that these effects arise from reorganization of atom and charge transfer mechanism in alloys. (c) 2013 Elsevier Ltd. All rights reserved.Öğe Alloying effect on K X-ray intensity ratio and production cross section values of Zn and Cr in Zn-Cr alloys (vol 87, pg 6, 2013)(Pergamon-Elsevier Science Ltd, 2015) Dogan, M.; Tirasoglu, E.; Karahan, I. H.; Aylikci, N. Kup; Aylikci, V.; Kahoul, A.; Cetinkara, H. A.[Abstract Not Available]Öğe Alloying effect on K X-ray intensity ratios, K X-ray production cross-sections and radiative Auger ratios in superalloys constitute from Al, Ni and Mo elements(Elsevier Science Bv, 2010) Aylikci, N. Kup; Tirasoglu, E.; Karahan, I. H.; Aylikci, V.; Eskil, M.; Cengiz, E.In this study, sigma(K alpha,beta) production cross-sections, K-beta/K-alpha, KLM/K-alpha and KMM/K-beta RAE intensity ratios of Ni and sigma(K alpha), sigma(K beta 1,2) production cross-sections, K-beta 1,K-3/K-alpha, K-beta 2,K-4/K-alpha, K-beta 2,K-4/K-beta 1,K-3, KLM/K-alpha and KMM/K-beta RAE intensity ratios of Mo have been measured in pure metals and in superalloy specimens. The samples were excited by 59.5 keV gamma-rays from a Am-241 annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect of alloying on the fluorescence parameters of Ni and Mo, phase structure, and corrosion behavior were investigated. The X-ray fluorescence parameters of Ni and Mo in superalloys indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena in superalloys. (C) 2010 Elsevier B.V. All rights reserved.Öğe Alloying effect on K-shell fluorescence parameters of porous NiTi shape memory alloys(Elsevier Science Bv, 2014) Cengiz, E.; Ozkendir, O. M.; Kaya, M.; Tirasoglu, E.; Karahan, I. H.; Kimura, S.; Hajiri, T.The K-alpha,K-beta shell production cross-sections and K-beta/K-alpha intensity ratios of porous Ni -49 at% Ti shape memory alloys were determined using energy dispersive X-ray fluorescence (EDXRF) technique. Also, the alloying effect on the K shell fluorescence parameters was investigated. The samples were excited by 59.5 key gamma-rays from an Am-241 annular radioactive source. The K X-rays emitted by the samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 key. The structure analyses of the samples were also made using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The deviations between the present results and theoretical values, calculated for pure Ti and Ni, were attributed to charge transfer phenomena and/or rearrangement of valance shell electrons and porosity. (C) 2014 Elsevier B.V. All rights reserved.Öğe Assessment of the mass attenuation parameters with using gamma-rays for manganese substituted nano hydroxyapatite(Pergamon-Elsevier Science Ltd, 2019) Koksal, O. K.; Apaydin, G.; Tozar, A.; Karahan, I. H.; Cengiz, E.Manganese substituted hydroxyapatite nanoparticles (nMnHAp) were produced using the ultrasonic wet chemical method. The elemental analysis was performed using Scanning Electron Microscopy (SEM) with integrated Energy Dispersive X-ray Spectrometry (EDX). The mass attenuation coefficients of manganese substituted hydroxyapatite nanoparticles have been measured at 59.5 keV gamma energy emitted from Am-241 radioisotope annular source with 50 mCi activity by using Ultra Low Energy Germanium Detector. These values are found to be in good agreement with theoretical values based on calculated XCOM data. Electron densities and effective atomic numbers were calculated by using the mass attenuation coefficients. Also, the mass attenuation coefficient of the real bone was determined as experimentally. The obtained results may provide information on how much radiation is transmitted through the sample when they are exposed to gamma-rays at 59.5 keV by comparing real bone.Öğe Chemical Analysis of Hydroxyapatite Artificial Bone Powders by Energy Dispersive X-Ray Fluorescence Spectrometry (EDXRF)(Office Spectroscopy & Spectral Analysis, 2018) Koksal, O. K.; Apaydin, G.; Cengiz, E.; Samek, L.; Karahan, I. H.; Tozar, A.; Lankosz, M.Stoichiometric hydroxyapatite (HA) nanoparticles were synthesized by a wet chemical method. Calcium nitrate tetra hydrate used as calcium source and dibasic ammonium phosphate used as phosphorous source. Calcium nitrate tetra hydrate and dibasic ammonium phosphate solutions were prepared by dissolving the salts in distilled water. Stoichiometric hydroxyapatite nanoparticles used by artificial bone powders and synthesized by a wet chemical method were analyzed using EDXRF method. The concentrations of K, Ca, Ti, V, Cr, Fe, Ni, Cu, Sr and Pb for artificial bone powders have been determined. Besides, Calcium contents were evaluated according to the agitation time and temperature in the production process.Öğe A Comparison for Grain Size Calculation of Cu-Zn Alloys with Genetic Programming and Neural Networks(Polish Acad Sciences Inst Physics, 2015) Karahan, I. H.; Ozdemir, R.Neural Networks (NN) and Genetic Programming (GP) were used as a new method for formulation of grain size of electrodeposited Cu1-xZnx alloys as a function of Zinc and Copper content both electrolyte and the alloy films produced by electrodeposition technique. To predict grain size a great number of different expression models genetic programming and neural network were conducted. Each model differs from the other with their linking function, number of genes, head size, and chromosomes. To generate databases for the new grain size formulations, testing and training sets in total of 134 samples were selected at different Zn and Cu ratios of components. 6 different input parameters were selected and the output parameter was grain size of the electrodeposited Cu-Zn alloys. The testing and training sets consisted of randomly selected 106 and 28 for the proposed models. All results in the models indicated an applicable performance for predicting grain size of the alloys and found reliable. The predicted model showed that all of the input parameters effected on the resulting grain size. The NN and GEP based formulation results are compared with experimental results and found to be quite reliable with a very high correlation (R2 = 0.995 for GEP and 0.999 for NN).Öğe Corrosion inhibition performance of polymer-alloy bilayer coatings: electropolymerised polyaniline and electrodeposited ZnNi with different layer orders(Maney Publishing, 2014) Karahan, I. H.; Tozar, A.Polyaniline (PANI) conducting polymer coatings have been obtained galvanostatically with various current densities (from 0.1 to 0.4 mA cm(-2)) and ZnNi alloy coatings have been obtained galvanostatically at 30 mA cm(-2) current density. Corrosion protection performances of monolayered PANI and ZnNi alloy coatings and multi-layered ZnNi/PANI and PANI/ZnNi coatings on st-37 low carbon mild steel (MS) have been investigated by an open circuit potential method, Tafel extrapolation method and electrochemical impedance method in 3.5 wt-% NaCl solution. In addition, the surface morphology of the coatings has been characterised by using scanning electron microscopy (SEM). Synthesising PANI films between two metal layers provided better corrosion protection to the steel. MS/PANI/ZnNi layer formation exhibited the biggest corrosion protection performance among all layer formations of the films and protected MS for up to 72 h.Öğe Corrosion Properties of AISI 4140 Industrial Steels Coated with Aniline in Different Storage Conditions(Polish Acad Sciences Inst Physics, 2016) Karahan, I. H.Polyaniline (PANI) was successfully deposited by means of cyclic voltammetry technique from 0.10 M aniline containing 0.30 M oxalic acid and 1 g/l H3BO3 solution on AISI 4140 steel electrode. In this investigation nominate scan rates 25, 50, 75, and 100 mV/s have been examined. PANI film was characterized using optical microscope; it was covered with a dark green-yellow homopolymer film of strongly adherent homogeneous characteristic. The corrosion behaviour of the steel electrodes with and without PANI film in 3.5% NaCl solution was investigated through anodic polarization curves. The results indicated that PANI coating led to decrease of the permeability of metallic plating. The PANI homopolymer film provided an effective barrier property and a remarkable anodic protection to substrate.Öğe A Cyclic Voltammetry Study on Electrodeposition of Cu-Zn Alloy Films: Effect of Ultrasonication Time(Polish Acad Sciences Inst Physics, 2017) Yurdal, K.; Karahan, I. H.Copper zinc alloys were electrodeposited in the form of thin films. Electrodeposition process was carried out in non-cyanide aqueous medium, under constant current. Effect of pre-deposition ultrasonication of solution was investigated. In other words ultrasonic treatment was applied only before the electrodeposition. Solutions were subjected to high-energy ultrasonication for increasing times. Cyclic voltammetry was used to understand changes occurring due to duration of ultrasonication. No ultrasonication was applied during deposition. Atomic composition of resultant films were revealed by MP-AES. It was found that implementation of ultrasonic treatment before electrodeposition affects CV characteristics, when compared to non-ultrasonicated solution. Atomic composition of fabricated samples were found to be close to each other, some of them showing more deviation.Öğe Effect of Borax Pentahydrate Addition to Acid Bath on the Microstructure and Corrosion Resistance of Zn-Co Coating(Polish Acad Sciences Inst Physics, 2015) Karahan, I. H.In this work, the Zn-Co coatings were synthesized on AISI 4140 steel and aluminum plates by using potentio-static electrodeposition technique in sulphate-based acidic baths with 0, 20, 40 and 60 gl(-1) of borax pentahydrate, as additive. The effect of borax pentahydrate on the microstructure of the samples was observed using scanning electron microscopy and X-ray diffractometer. The deposition process was investigated by cyclic voltammetry. The effect of borax pentahydrate on the corrosion resistance of the samples was studied by potentiodynamic polarization technique. The results have demonstrated, that the addition of borax pentahydrate was in favor of the growth of grains. The morphology of pyramidal islands on the surface was changed to a more flat structure. The results have also demonstrated that the effect of borax pentahydrate was not monotonous. With increasing concentration, the corrosion potential was at minimum and the charge transfer resistance R-t was at maximum for the sample obtained from the bath with 60 gl(-1) of borax pentahydate, indicating that this sample showed the best corrosion resistance. It was found that current density first decreased and than increased, due to adsorption of a complex of borax pentahydrate and/or changes in the morphology, however, the initial deposition potential was not affected. The addition of borax pentahydrate to the bath led to formation of the best Zn-Co deposits, composed of coalesced globular fine grains, smaller than approximate to 2 mu m in diameter. In addition, all of the studied Zn-Co deposits consisted of eta phases. It is suggested that Zn-Co deposits produced in the bath containing 60 gl(-1) of borax pentahydrate probably offer sacrificial protection to the steel substrate.Öğe Effect of current density on the corrosion protection performance of polyaniline coated AISI 4140 steel(Taylor & Francis Ltd, 2019) Karahan, I. H.The present work reports on electropolymerisation of aniline onto AISI 4140 steel substrate at room temperature in oxalic acid media by the potentiodynamic electrodeposition method. The effect of coating current density on the morphology of conductive polymer films and their corrosion behaviour has been investigated. The electrolyte solution comprised 0.1 M aniline + 0.3 M oxalic acid. The effects of deposition current density changes (0.1, 0.2, 0.3, 0.4 and 0.5 mA cm(-2)) on the films were investigated. The PANI film was characterised using cyclic voltammetry and optical microscopy; it was covered with a dark green-yellow homopolymer film of strongly adherent homogeneous characteristic. The corrosion behaviour of steel electrodes with and without polyaniline (PANI) film in 3.5 wt-% NaCl solution was investigated through anodic polarisation curves. The results indicated that the PANI coating obtained under 0.2 mA cm(-2) was the most corrosion protective.Öğe The effect of metal rate on the gamma shielding parameters of hydroxyapatite at medical treatment energies(Pergamon-Elsevier Science Ltd, 2022) Koksal, O. K.; Apaydin, G.; Karahan, I. H.; Tozar, A.The hydroxyapatite (HAp) is a kind of biomaterial which is used for bone treatment applications. We have scrutinized the gamma attenuation parameters such as such as the effective atomic number (Zeff), electron density (Nel), mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half value layer (HVL), tenth value layer (TVL) and mean free path (MFP) for only single liquid gamma source and a narrow beam geometry for the energy (medical treatment energy) ranging from 778 keV to 1408 keV (Eu-152) for the animal bone, iron, cobalt, copper, and zinc decorated Nano hydroxyapatite (nFeHAp, nCoHAp, nCuHAp, and nZnHAp) artificial bone powders. The gamma-rays were counted with using Ultra Low Energy Germanium detection system with a resolution 150 eV at 5,95 keV and a high purity germanium detector with a resolution of 1.85 keV at 1.33 MeV experimentally. The gamma ray attenuation parameters are calculated for the metal doped hydroxyapatite and compare with the animal bone. The results were compared with the output XCOM NIST data. While the mass absorption coefficient values for animal bone range from 0.08 to 0.05 at current energy levels, the values for metal-added artificial bone powders range from 0.07 to 0.05. While the linear absorption coefficient values for existing energy values for animal bone range from 0.04 to 0.02, they range from 0.03 to 0.02 for metal-added artificial bone powders. Mean free path values for real bone range from 24 to 36 at current energies, while half value layer values range from 16 to 25 and tenth value layer values range from 56 to 83. For metaldoped artificial bone powders, these parameters range from 26 to 35, 18 to 24, and 61 to 80, respectively. The results points that, the data of the gamma ray attenuation parameters are very close to the value of the animal bone due to the removal of calcium atoms from the structure when metal is added.Öğe Effect of pH treatment on K-shell x-ray intensity ratios and K-shell x-ray-production cross sections in ZnCo alloys(Amer Physical Soc, 2011) Aylikci, N. Kup; Aylikci, V.; Kahoul, A.; Tirasoglu, E.; Karahan, I. H.; Cengiz, E.In this study, empirical and semiempirical K-shell fluorescence yields (omega(K)) and K beta/K alpha intensity ratios from the available experimental data for elements with 23 <= Z <= 30 were calculated to compare them with elements in different alloys. The experimental data are fitted using the quantity [omega(K)/(1 -omega(K))](1/4) vs Z to deduce the empirical K-shell fluorescence yields and K beta/K alpha intensity ratios. The empirical and semiempirical K-shell fluorescence yield values were used to calculate the K x-ray-production cross-section values for pure Co and Zn elements. Also, sigma(K alpha), sigma(K beta) production cross sections and K beta/K alpha intensity ratios of Co and Zn have been measured in pure metals and in different alloy compositions which have different pH values. The samples were excited by 59.5-keV. rays from a Am-241 annular radioactive source. K x rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect of pH values on alloy compositions and the effect of alloying on the fluorescence parameters of Co and Zn were investigated. The x-ray fluorescence parameters of Co and Zn in the alloying system indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena.Öğe Effect of solution Zn concentration on electrodeposition of CuxZn1-x alloys: materials and resistivity characterisation(Taylor & Francis Ltd, 2019) Ozdemir, R.; Karahan, I. H.CuxZn1-x alloy films were electrodeposited from non-cyanide sulphate solutions. Solution zinc ion concentration was varied, while that of copper was kept constant. Cyclic voltammetry studies from solutions showed that change in zinc ion molarity causes differences in electrolyte characteristics and resulting films. Morphology, elemental composition and phase structures of electrodeposited samples were characterised using SEM, EDS and XRD, respectively. Additionally, resistivity measurements were carried out on films using the four-point probe method. Results show that change of solution zinc concentration affects morphological, elemental and structural properties of deposited films, which consequently results in different electrical resistivity behaviour.Öğe Effects of Blanking Speed on the Shear Surface of Mild Steel (St37)(Polish Acad Sciences Inst Physics, 2016) Kanca, E.; Eyercioglu, O.; Karahan, I. H.; Gunen, A.; Gov, K.Blanking operation is widely used to cut sheet or plates by a shearing process between punch and die. The process of shearing and the conditions of the sheared surface are influenced by the punch, the die, the speed of punching, the clearance between the punch and the die. In this study, effects of high speed blanking on surface quality and corrosion properties of mild steel St37 shear surface have been investigated. The work presented in this paper aims at evaluating the shear surface quality improvements of the St37 resulting from the use of high energy rate forging machine. The appraisal is based on criteria related to surface accuracy and corrosion resistance characterization. For this purpose, St37 mild steels were cut using three different punch speeds hydraulic presses at nearly quasistatic, conventional mechanical presses at low punch velocity (0.2 m/s) and high energy rate forging machine at high punch velocity (10 m/s), for different die clearances (4.5%-6% of sheet thickness). After accelerated corrosion tests, blanks were performed in conjunction with scanning electron microscopy technique to study the cutting process of the blanks at room temperature. In fact, by using high energy rate forging machine, a reduction of more than 25% of the surface roughness (R-a) was realized and better resistance to stress corrosion cracking and pitting corrosion was noticed. It was observed that the corrosion resistance of the high energy rate forging-cut specimen was better than that of the hydraulic-cut and mechanical-cut specimens.Öğe Effects of ultrasonic agitation prior to deposition and additives in the bath on electrodeposited Ni-B/hBN composite coatings(Elsevier Science Sa, 2018) Unal, E.; Karahan, I. H.Ni-B/hBN composite coatings were successfully deposited by conventional electroplating method on mild steel substrate. Electrodeposition was carried out in Watts type nickel electrolite and trimethylamine borane (TMAB) was used as boron element source. hBN particles with 1 um average powder size were used as reinforcements. In this study, the effects of additives in the bath and ultrasonic mixing before deposition on the composite coating properties were evaluated. Crystal structure, morphology and composition of composite coatings were investigated by X-ray diffraction analysis, scanning electron microscopy and energy dispersive spectroscopy. Also corrosion behavior of composite coatings was analysed via Tafel extrapolation and open circuit potential techniques in 3.5% wt. NaCI solution. The results showed that the composite coatings that have compact and smooth properties were obtained and ultrasonic agitaiton significantly influenced corrosion resistance of composite coatings and uniform distribution of incorporated hBN particles. It was found that corrosion rate of the composite coatings was 76.7% and 78.5% lower than that of composite coatings produced in the bath without ultrasonic mixing and without ultrasonic mixing plus additives, respectively. (C) 2018 Elsevier B.V. All rights reserved.Öğe Electrodeposition and characterisation of Zn, Zn-Fe and Zn-Fe-Ni coatings in presence of gelatin as additive(Taylor & Francis Ltd, 2008) Karahan, I. H.; Cetinkara, H. A.; Gueder, H. S.Studies of the factors that enhance the corrosion behaviour of electrodeposited Zn, Zn-Fe and Zn-Fe-Ni coatings are highly relevant due to the considerable industrial use of these alloys as protective coatings for steel substrates. This paper reports on the corrosion behaviour and structure of Zn, Zn-Fe and Zn-Fe-Ni coatings deposited from an acid citrate solution studied in the absence and in the presence of gelatin as additive. The presence of Fe or Fe-Ni in the Zn matrix increases Zn coating corrosion resistance. The presence of gelatin in the plating bath increases the corrosion resistance of Zn, Zn-Fe and Zn-Fe-Ni coatings.Öğe Electrodeposition and Corrosive Properties of Environmental ZnFe/Polyaniline on Low Carbon Steel(Polish Acad Sciences Inst Physics, 2016) Karahan, I. H.; Tiltil, F.Zinc-iron alloy plating (ZnFe) was successfully deposited on AISI 4140 steel applying cyclic voltammetry technique. Polyaniline (PANI) film was synthesized with cyclic voltammetry technique from 0.10 M aniline containing 0.30 M oxalic acid solution on zinc-iron plated carbon steel (AISI4140/ZnFe) electrode. ZnFe film was characterized by scanning electron microscopy and X-ray diffraction technique. The corrosion behaviour of zinc-iron deposited carbon steel electrodes with and without PANI film in 3.5% NaCl solution was investigated with polarization curves. Effect of pH and current density on the synthesis of the aniline was also examined. The results showed that PANI coating led to decrease of the permeability of metallic plating. The PANI homopolymer film provided an effective barrier property on zinc-iron coating and a remarkable anodic protection to substrate. ZnFe particles had more homogeneous, smooth prismatic structure. It is suggested that ZnFe/PANI deposits produced in the bath applying 0.1 mA/cm(2) current density probably offer bigger protection to the steel substrate.
