Browsing by Author "Aslan, M."

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The Effect of Magnetic Field on the Wear Properties of a Ferromagnetic Steel
(Elsevier Science SA, 2013) Yetim, A. F.; Kovaci, H.; Aslan, M.; Celik, A.
Numerous machine components are constantly subject to different magnetic fields mainly due to the environments they are in, and they show some wear process throughout their life time. To understand this wear process better, the effect of magnetic field on the tribological properties of AISI 4140 steel has been investigated by applying different magnetic field intensities. One of the important factors affecting the wear and friction properties of a tribological system is wear debris and their properties like chemical structure and movement between mating bodies. For this respect, magnetic field was applied on a ferromagnetic material both before and during wear tests. Then, tribological properties of the samples magnetized before the wear tests were compared with the samples to which magnetic field was applied during the tests. It was observed that samples subjected to the magnetic field during tests showed better wear resistance and lower friction coefficient values than the others as the magnetized wear debris produced during test could be removed between mating bodies by means of magnetic effect while oxidized debris were held at the rubbing interface and lowered the debris production. (C) 2012 Elsevier B.V. All rights reserved.
The Effect of Plasma Oxidation and Nitridation on Corrosion Behavior of CoCrMo Alloy in SBF Solution
(World Scientific Publ Co Pte Ltd, 2018) Aslan, M.; Comakli, O.; Yazici, M.; Yetim, A. F.; Bayrak, O.; Celik, A.
The present study was focussed on investigating the corrosion properties of plasma-oxidized and -nitrided CoCrMo alloys under different conditions. The structural properties of untreated and treated samples were examined by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Corrosion behavior of samples was mainly investigated by potentiodynamic polarization and electrochemical impedance spectroscopy in simulated body fluid solution. The results showed that corrosion resistance of the oxidized layers was better than that of the nitrided ones. The corrosion resistance of the alloys increased as the plasma oxidation process temperature and time increased. However, the corrosion resistance of the alloys reduced with increase in the process temperature and time after plasma nitriding process.
The Effect of Surface Plastic Deformation Produced by Shot Peening on Corrosion Behavior of a Low-Alloy Steel
(Elsevier Science SA, 2019) Kovaci, H.; Bozkurt, Y. B.; Yetim, A. F.; Aslan, M.; Celik, A.
Shot peening treatment is a well-known and practical method to improve surface properties of materials. In this method, surfaces of materials are peened by small steel shots and thus, surface hardening is provided. Although it is used in a wide range of applications, this process could affect the electrochemical behavior of materials because of changing surface properties. Therefore, the effects of shot peening process on the electrochemical properties of a low-alloy steel were examined in the present study. AISI 4140 low-alloy steel samples were shot peened in different intensities of 16 A, 18 A, 20 A and 24 A. Afterwards, corrosion tests were carried out at room temperature in a 3.5% NaCl solution. Open circuit potential (OCP) electrochemical polarization and electrochemical impedance spectroscopy (EIS) analysis were performed in corrosion tests. The microstructural, morphological and surface properties of samples were analyzed by XRD, SEM and 3D surface profilometer. The structural analyses showed that grain structure of the material was affected by shot peening treatment. A plastically deformed zone, which have extended and refined grain structure, formed after shot peening processes. Electrochemical analyses indicated that the corrosion resistance of the material increased with the increasing shot peening intensity owing to grain refinement and formation of sub-grains. Also, examinations on the corroded surfaces showed that crevice corrosion was the main mechanism for shot peened samples.
The Effect of Wettability on Corrosion Resistance of Oxide Films Produced by Silar Method on Magnesium, Aluminum and Copper Substrates
(Elsevier Science Sa, 2016) Akaltun, Y.; Aslan, M.; Yetim, T.; Cayir, T.; Celik, A.
The CuO, MgO and Al2O3 films were deposited on Cu, Mg and Al substrates by the Successive Ionic Layer Adsorption and Reaction (SITAR) method. While the MgO thin film showed hydrophilic behavior with contact angle of 75, the Al2O3 film was hydrophobic with the contact angle of 117 degrees. The best enhancement in terms of the wetting behavior was obtained from the copper oxide films. For these films, maximum static water contact angle was 164 degrees. Results showed super-hydrophobic property and unique shape of form. Moreover, the superhydrophobic surface of CuO film exhibited higher corrosion resistance than MgO and Al2O3 films. (C) 2016 Elsevier B.V. All rights reserved.