Yazar "Kanca, Yusuf" seçeneğine göre listele

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    A comparative study on the effects of different thermochemical coating techniques on corrosion resistance of STKM-13A steel
    (Springer Boston, 2018) Günen, Ali; Kanca, Yusuf; Karahan, İsmail Hakkı; Karakaş, Mustafa Serdar; Gök, Mustafa Sabri; Kanca, Erdoğan; Çürük, Ahmet
    The corrosion resistances of three different thermochemical coatings (grown using titanizing, boriding, and borotitanizing treatments) applied to STKM-13A steel surfaces were investigated. The coatings were characterized using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, 2D profilometry, and microhardness experiments. The corrosion tests were conducted using both electrochemical and static immersion methods, in 3.5 pct NaCl and 40 pct HF acid solutions, respectively. The corrosion resistance of STKM-13A steel was enhanced after the coating process. The specimens were exposed to more corrosion in the HF solution than in the NaCl solution. The best corrosion resistance was obtained in the borotitanized and borided specimens immersed in the NaCl and HF solutions, respectively. The borided STKM-13A steel sample showed even less cumulative weight loss than Inconel 625 in the static immersion HF acid solution test. This suggests potential use of the borided STKM-13A steel in the uranium production units of nuclear power plants as an alternative to more costly alternatives such as Monel, Inconel, and Hastelloy. © 2018, The Minerals, Metals & Materials Society and ASM International.
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    High temperature wear behavior of the surface-modified externally cooled rolls
    (Elsevier B.V., 2018) Günen, Ali; Kanca, Erdoğan; Karakaş, Mustafa Serdar; Koç, Vahdettin; Gök, Mustafa Sabri; Kanca, Yusuf; Çürük, Ahmet; Demir, Mehmet
    Externally cooled rolls of a steel plant were coated using three different surface modification techniques, namely titanizing, boronizing and borotitanizing. The grown coatings were examined using optical microscopy, scanning electron microscopy, microhardness measurements, X-ray diffraction and Raman analysis. Depending on the coating technique, a wide range of coating thicknesses and microhardness values were obtained; the highest microhardness was obtained in the titanized sample, while the greatest coating thickness was obtained in the borotitanized sample. Wear tests were performed on the untreated and coated specimens using a ball-on-disc wear tester under two different loads (1 N, 3 N) at three different temperatures (25 °C, 250 °C, 450 °C). The average friction coefficient values decreased at elevated temperatures, and increased under increased load. Temperature had a significant effect on the wear mechanism. At room temperature the effective wear mechanism was delamination, while at 250 °C and 450 °C oxidative wear was observed. All of the surface modification treatments improved the wear resistance. The highest wear resistance was observed in the borotitanized sample. © 2018 Elsevier B.V.
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    Hydrophobic surface modification and characterization of melamine foam
    (TUBİTAK, 2023) Okutan, Merve; Boran, Filiz; Ergün, Ayça; Kanca, Yusuf; Özkahraman, Bengi; Deligöz, Hüseyin
    Abstract: Superhydrophobic and oleophilic modification of commercial acoustic melamine foam (MF) was made in this study. The modification was carried out with chitosan (CHI) and silica particles (SiO2 ), by using both a layer-by-layer-like approach (LbL) and dip coating technique. Subsequently, 1-octadecanethiol was used as a secondary modification agent. QCM-D, SEM, and FTIR analyses confirmed that the coating was successfully performed. After the modification, the column wall thicknesses increased than that of MF and they ranged from 25% to 48% for modified MF with an LbL-like approach (MMF) and modified MF via dip coating technique (MMFd), respectively. The sorption experiments showed that modified MFs, which had a water contact angle (WCA) above 160°, could sorb several model pollutants (vegetable oil, chloroform, ethanol, and toluene) up to 76–130 times their original weight. It had been determined that MMF protects its open-pore structure better than that of MMFd, which indicated that MF has a more uniform pore structure after modification. Furthermore, after 10 cycles of the sorption and release process, there was no significant change in sorption capacity, and they preserved their mechanical stability and flexibility
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    Properties and Corrosion Resistance of AISI H13 Hot-Work Tool Steel with Borided B4C Powders
    (Korean Inst Metals Materials, 2020) Gunen, Ali; Karahan, Ismail Hakki; Karakas, Mustafa Serdar; Kurt, Bulent; Kanca, Yusuf; Cay, Vedat Veli; Yildiz, Murat
    In this study, the surface of AISI H13 steel was borided with powder blends of B4C and NaBF(4)using the powder-pack method at 800, 900 and 1000 degrees C for 2, 4 and 6 h. The structural and mechanical characteristics of the boride layers formed on the surface were characterized using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, 2D surface profilometry, microhardness and electrochemical corrosion (3.5 wt% NaCl) tests. The boride layer exhibited a single phase structure (Fe2B) in samples coated at 800 degrees C and a dual-phase structure (FeB + Fe2B) at higher boriding temperatures (900 and 1000 degrees C). The boride layers were compact and crack-free in all boriding conditions. Depending on boriding parameters, the thickness, hardness and average surface roughness (R-a) of the coatings were found to range between 5.81 and 102.46 mu m, 1635-1915 HV and 0.315-0.650 mu m, respectively. The borided AISI H13 steel displayed up to 33.5 times and 2.4 times higher corrosion resistance than untreated AISI H13 steel and martensitic AISI 431 steel, respectively. This suggests potential use of borided AISI H13 steel in the steam turbines and marine applications as an alternative to the more costly martensitic and duplex stainless steel grades. The corrosion resistance depended on the phase structure (single- or dual-layer), density, thickness and surface roughness of the boride coatings. Graphic
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    Properties and tribologic behavior of titanium carbide coatings on AISI D2 steel deposited by thermoreactive diffusion
    (Minerals, Metals and Materials Society, 2018) Kurt, Bülent; Günen, Ali; Kanca, Yusuf; Koç, Vahdettin; Gök, Mustafa Sabri; Kırar, Ersan; Askerov, Khangardash
    In the present study, the metallographic, mechanical and tribologic behaviors of AISI D2 steel specimens coated with TiC through the titanizing process were investigated. The titanizing treatment was performed at the temperatures of 900°C, 1000°C or 1100°C for 1 h, 2 h or 3 h using a solid-state box thermoreactive diffusion technique. In all cases, the predominant phase in the coating was TiC, but the mechanical properties of the coating varied with treatment condition. The wear resistance of the coated samples against a linear reciprocating Al2O3 ball improved as the hardness and thickness of the coating increased. The effective wear mechanism of samples that had been treated at 900°C, 1000°C and 1100°C were severe plastic deformation, delamination and polishing type wear, respectively. The wear performance was affected by coating layer’s thickness and uniformity as well as its surface hardness, elastic modulus and toughness. © 2018, The Minerals, Metals & Materials Society.
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    Tribological evaluation of biomedical polycarbonate urethanes against articular cartilage
    (Elsevier Science Bv, 2018) Kanca, Yusuf; Milner, Piers; Dini, Daniele; Amis, Andrew A.
    This research investigated the in-vitro wear and friction performance of polycarbonate urethane (PCU) 80A as they interact with articular cartilage, using a customised multidirectional pin-on-plate tester. Condyles were articulated against PCU 80A discs (Bionate(center dot) I and Bionate(center dot) II) (configuration 1) and the results arising from these tests were compared to those recorded during the sliding of PCU pins against cartilage plates (configuration 2). Configuration 1 produced steadily increasing coefficient of friction (COF) (up to 0.64 +/- 0.05) and had the same trend as the cartilage on stainless steel articulation (positive control). When synovial fluid rather than bovine calf serum was used as lubricant, average COF significantly decreased from 0.50 +/- 0.02-0.38 +/- 0.06 for condyle on Bionate(center dot) I (80AI) and from 0.41 +/- 0.02-0.24 +/- 0.04 for condyle on Bionate(center dot) II (80AII) test configurations (p < 0.05). After 15 h testing, the cartilage on cartilage articulation (negative control) tests showed no cartilage degeneration. However, different levels of cartilage volume loss were found on the condyles from the positive control (12.5 +/- 4.2 mm(3)) and the PCUs (20.1 +/- 3.6 mm(3) for 80 AI and 19.0 +/- 2.3 mm(3) for 80AII) (p > 0.05). A good correlation (R-2 = 0.84) was found between the levels of average COF and the volume of cartilage lost during testing; increasing wear was found at higher levels of COF. Configuration 2 showed low and constant COF values (0.04 +/- 0.01), which were closer to the negative control (0.03 +/- 0.01) and significantly lower than configuration 1 (p < 0.05). The investigation showed that PCU is a good candidate for use in hemiarthroplasty components, where only one of the two articulating surfaces is replaced, as long as the synthetic material is implanted in a region where migrating cartilage contact is achieved. Bionate(center dot) II showed better tribological performance, which suggests it is more favourable for use in hemiarthroplasty design.
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    Tribological properties of PVA/PVP blend hydrogels against articular cartilage
    (Elsevier Science Bv, 2018) Kanca, Yusuf; Milner, Piers; Dini, Daniele; Amis, Andrew A.
    This research investigated in-vitro tribological performance of the articulation of cartilage-on-polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) blend hydrogels using a custom-designed multi-directional wear rig. The hydrogels were prepared by repeated freezing-thawing cycles at different concentrations and PVA to PVP fractions at a given concentration. PVA/PVP blend hydrogels showed low coefficient of friction (COF) values (between 0.12 +/- 0.01 and 0.14 +/- 0.02) which were closer to the cartilage-on-cartilage articulation (0.03 +/- 0.01) compared to the cartilage-on-stainless steel articulation (0.46 +/- 0.06). The COF increased with increasing hydrogel concentration (p = 0.03) and decreasing PVP content at a given concentration (p < 0.05). The cartilage-on-hydrogel tests showed only the surface layers of the cartilage being removed (average volume loss of the condyles was 12.5 +/- 4.2 mm(3)). However, the hydrogels were found to be worn/deformed. The hydrogels prepared at a higher concentration showed lower apparent volume loss. A strong correlation (R-2 = 0.94) was found between the COF and compressive moduli of the hydrogel groups, resulting from decreasing contact congruency. It was concluded that the hydrogels were promising as hemiarthroplasty materials, but that improved mechanical behaviour was required for clinical use.