Malzeme Bilimi ve Mühendisliği Bölümü

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Citation - WoS: 9
Citation - Scopus: 11
Boriding kinetics and mechanical properties of borided commercial-purity nickel
(Natl inst Science Communication-niscair, 2017) Calik, A.; Ucar, N.; Delikanli, K.; Carkci, M.; Karakas, S.
Kinetics of boride layer growth and tensile behaviour in bonded commercial-purity nickel was investigated. Bonding was carried out in a solid medium consisting of Ekabor-II powders at 1173, 1223 and 1273 K for periods of 3, 5 and 8 h. Scanning electron microscopy (SEM) and optical microscopy showed column morphology in the boride layer. X-ray diffraction (XRD) analyses indicated that the boride layer formed on the surface consisted mainly of Ni2B, with precipitates of Ni6Si2B. A parabolic relationship between layer thickness and processing temperature was observed. The obtained results showed that although the boride layer thickness increased with increasing boriding temperature and time, boriding parameters had no significant effect on the hardness of the boride layer or the matrix. Tensile properties were negatively influenced by the bonding treatment; both yield and tensile strength values decreased due to the presence of the hard yet brittle surface coating. In addition, the growth kinetics of boride layers was also analysed. The results showed a nearly parabolic relationship between the layer thickness and the process temperature, with activation energy of 47.3 kJ mol(-1).
Citation - WoS: 0
Citation - Scopus: 0
Diffusion Kinetics of Binary Ti-Ni Shape Memory Alloys
(Polish Acad Sciences inst Physics, 2017) Ucar, N.; Karakaş, Mustafa Serdar; Dogan, S.; Ozdemir, A. F.; Karakas, S.; Calik, A.; 48915; Malzeme Bilimi ve Mühendisliği
In this work, the boriding of binary Ti-Ni shape memory alloys was carried out in a solid medium at 1173 and 1273 K for 2, 4, and 8 h using the powder pack method with Ekabor-Ni powders. The boride layer was characterized by optical microscopy and scanning electron microscopy. The obtained results show that boride layer thickness increases with the increasing boriding temperature and time. Depending on temperature and boride layer thickness, the diffusion process is thermally activated, with the mean value of the activation energy being close to 67 kJ/mol.
Citation - WoS: 5
Citation - Scopus: 5
Investigation of the Erosive Wear Resistance of Boronized Ash-Blowing Nozzles
(Polish Acad Sciences inst Physics, 2017) Calik, A.; Ozbakir, O.; Karakas, S.; Ucar, N.; 48915
In this study, pack boronizing was applied to ash-blowing nozzles manufactured from AISI 1040 steels using Ekabor II powders as the boronizing source at a temperature of 1273 K for a duration of 8 h. Erosive wear tests of boride ash-blowing nozzles were carried out in ash delivery line of thermal reactor under actual working conditions. It was observed that erosive wear resistance of borided ash-blowing nozzles were increased 3 times as a result of the boronizing process. The improved wear resistance of the borided samples can be explained by increased surface hardness and higher work hardening.
Citation - WoS: 0
Citation - Scopus: 0
Synthesis, molecular structure and DFT study of 2-(N-Benzoylbenzamido)pyridine-3-yl benzoate
(Springer/plenum Publishers, 2011) Yuksektepe, Cigdem; Özdoğan, Cem; Kazak, Canan; Ozdogan, Cem; Guvenc, Ziya B.; Buyukgungor, Orhan; Arslan, Figen; Odabasoglu, Mustafa; 42359; 22620; 4292; 49272; 13249; Ortak Dersler Bölümü
The biologically important 2-amino-3-hydroxypyridine reacts with benzoyl chloride to give 2-(N-benzoylbenzamido)pyridine-3-yl benzoate. This synthesized compound has been studied by elemental analysis, X-ray crystallography and also theoretically by density functional theory (DFT) framework with B3LYP/6-311++G(d, p) level of theory. The molecules of this compound crystallize in the orthorhombic space group of P2(1)2(1)2(1) and the crystal packing involves both hydrogen-bonding and C-Ha <-pi interaction. The vibrational normal modes of the molecular structure are investigated by ab initio method for both infrared intensities (IR) and for Raman activities. Furthermore, the corresponding assignments are discussed. Hydrogen and carbon atoms of the benzene rings are found to be highly active. Also, experimentally obtained IR spectrum is presented and compared with the available theoretical data. Experimentally and theoretically obtained IR spectrum are in good agreement.

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