Browsing by Author "Kurt, Bülent"

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    Microstructural andWear Characteristics of High Velocity Oxygen Fuel (HVOF) Sprayed NiCrBSi–SiC Composite Coating on SAE 1030 Steel
    (Arabian Journal for Science and Engineering, 2011) Buytoz, Soner; Ulutan, Mustafa; Islak, Serkan; Kurt, Bülent; Çelik, O. Nuri
    In this paper, wear properties of NiCrBSi–SiC coatings were investigated using the ball-on-disk wear test. In experimental study, NiCrBSi–SiC powders were sprayed using a high-velocity oxygen fuel technique on an SAE 1030 steel substrate. Powder mixtures with different weight mixing ratios, NiCrBSi + 10 wt% SiC, NiCrBSi + 20 wt% SiC and NiCrBSi + 40 wt% SiC coatings were prepared. The deposited coatings are compared in terms of their phase composition, microstructure and hardness. It is proved that the degree of mixing of the NiCrBSi and SiC components in the powder has a massive effect on the phase composition, microstructure and hardness of the coatings.Wear tests were conducted on both the uncoated and coated substrates at same normal load, speed, and wear distance. It has been determined that the coated substrates exhibit a very good tribological performance in comparison to the uncoated substrate. The increase in the adhesive wear resistance provided by the coating has been attributed to the presence of a large amount of dispersed Ni and Cr carbide and/or borides in the Ni matrix.
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    Microstructural Characteristics of High Velocity Oxygen Fuel (HVOF) sprayed NiCrBSi-SiC Composite Coating on a Low Alloy Steel
    (6th International Advanced Technologies Symposium (IATS’11), 16-18 May 2011, 13-21, Elazığ,, 2011) Islak, Serkan; Buytoz, Soner; Kurt, Bülent
    In this study, NiCrBSi-SiC powders were sprayed using a high velocity oxygen fuel technique on AISI 1030 steel substrate. Powder mixtures with different weight mixing ratios, NiCrBSi+10 wt.% SiC, NiCrBSi+20 wt.% SiC and NiCrBSi+40 wt.% SiC coatings were prepared. The deposited coatings are compared in terms of their phase composition, microstructure and hardness. It is proved that the degree of mixing of the NiCrBSi and SiC components in the powder has massive effect on the phase composition, microstructure and hardness of the coatings. The structure and morphologies of Ni-based coatings were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) and optical microscope (OM). Microstructures of the coatings have been revealed to the presence of a large amount of dispersed Ni and Cr carbide and/or borides in the Ni matrix. Microhardness of the coatings is found to in the range of 550–830 Hv, which is higher than the substrate material
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    PLAZMA PÜSKÜRTME YÖNTEMİYLE OLUŞTURULAN AL2O3- TİO2 KOMPOZİT KAPLAMALARIN MİKROYAPI KARAKTERİSTİKLERİ
    (International Iron & Steel Symposium, 02-04 April 2012, Karabük, Türkiye, 2012) Buytoz, Soner; Ersöz, Emine; Islak, Serkan; Orhan, Nuri; Kurt, Bülent; Somunkıran, İlyas
    Yapılan çalışmada, SAE 1040 çeliğine plazma püskürtme yöntemiyle, Al2O3 tozu ve değişen oranlarda TiO2 tozu ilave edilerek Al2O3/TiO2 kompozit kaplamaları oluşturuldu. Elde edilen kaplama tabakalarının metalografi incelemeleri neticesinde lamelli bir mikroyapı içerisinde az miktarda ergimemiş partiküller, kısmi ergimiş ve tamamen ergimiş bölgeler gözlendi. Al2O3-TiO2 kompozit kaplamalarında TiO2 toz miktarının artmasına karşı gözenek miktarının azaldığı tespit edildi. XRD analizi sonuçları, kaplama tabakasında γ -Al2O3, α-Al2O3, Al2TiO5, ve TiO2 (rutil) fazlarının oluştuğunu göstermiştir. Kaplama tabakasının mikrosertliği alt malzemeye göre 3-4.5 kat daha fazladır. Kaplama tabakalarının ortalama mikrosertlik değerleri 650-850 HV arasında değişmiştir. In this study, Al2O3-TiO2 composite coatings were thermally sprayed on the SAE 1040 steel using atmospheric plasma spray (APS) process of mixed different rates of micron–sized TiO2 and micron-sized Al2O3 powders. The effects of TiO2 addition on the microstructure, phase compositions and microhardness of the coatings were investigated by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and microhardness tester. The results show that the Al2O3-TiO2 composite coatings consist of both fully melted regions, partially melted regions, and the unmelted particles in regions of lamellar-like structure. Phase transformations from mainly stable α-Al2O3 and anatase-TiO2 in the powders to predominant metastable γ-Al2O3, rutile-TiO2 and Al2TiO5 phase in the Al2O3-TiO2 composite coatings were observed. It was idendified that the pore content was decreased with increase of TiO2 powder ratio. The microhardnesses of the coating layers were found to be 3-4.5 times higher than that of substrate material. The average microhardness values of the coatings were changed as 650-860 HV.
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    PLAZMA PÜSKÜRTME YÖNTEMİYLE OLUŞTURULAN AL2O3- TİO2 KOMPOZİT KAPLAMALARIN MİKROYAPI KARAKTERİSTİKLERİ
    (International Iron & Steel Symposium, 02-04 April 2012, Karabük, Türkiye, 2012) Buytoz, Soner; Ersöz, Emine; Islak, Serkan; Orhan, Nuri; Kurt, Bülent; Somunkıran, İlyas
    Yapılan çalışmada, SAE 1040 çeliğine plazma püskürtme yöntemiyle, Al2O3 tozu ve değişen oranlarda TiO2 tozu ilave edilerek Al2O3/TiO2 kompozit kaplamaları oluşturuldu. Elde edilen kaplama tabakalarının metalografi incelemeleri neticesinde lamelli bir mikroyapı içerisinde az miktarda ergimemiş partiküller, kısmi ergimiş ve tamamen ergimiş bölgeler gözlendi. Al2O3-TiO2 kompozit kaplamalarında TiO2 toz miktarının artmasına karşı gözenek miktarının azaldığı tespit edildi. XRD analizi sonuçları, kaplama tabakasında γ -Al2O3, α-Al2O3, Al2TiO5, ve TiO2 (rutil) fazlarının oluştuğunu göstermiştir. Kaplama tabakasının mikrosertliği alt malzemeye göre 3-4.5 kat daha fazladır. Kaplama tabakalarının ortalama mikrosertlik değerleri 650-850 HV arasında değişmiştir.In this study, Al2O3-TiO2 composite coatings were thermally sprayed on the SAE 1040 steel using atmospheric plasma spray (APS) process of mixed different rates of micron–sized TiO2 and micron-sized Al2O3 powders. The effects of TiO2 addition on the microstructure, phase compositions and microhardness of the coatings were investigated by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and microhardness tester. The results show that the Al2O3-TiO2 composite coatings consist of both fully melted regions, partially melted regions, and the unmelted particles in regions of lamellar-like structure. Phase transformations from mainly stable α-Al2O3 and anatase-TiO2 in the powders to predominant metastable γ-Al2O3, rutile-TiO2 and Al2TiO5 phase in the Al2O3-TiO2 composite coatings were observed. It was idendified that the pore content was decreased with increase of TiO2 powder ratio. The microhardnesses of the coating layers were found to be 3-4.5 times higher than that of substrate material. The average microhardness values of the coatings were changed as 650-860 HV.
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    PLAZMA TRANSFERLİ ARK KAYNAK YÜZEY İŞLEMİYLE AISI 304 PASLANMAZ ÇELİK YÜZEYİNE WC-Ni-B4C KOMPOZİT KAPLAMASININ MİKROYAPISAL KARAKTERİSTİĞİ
    (e-Journal of New World Sciences Academy 2010, Volume: 5, Number: 1, Article Number: 1A0063, 2010) Buytoz, Soner; Ulutan, Mustafa; Kurt, Bülent; Islak, Serkan; Somunkıran, İlyas
    Bu çalışmada, AISI 304 paslanmaz çelik yüzeyine B4C-Ni-WC karbür ve element tozlar plazma transferli ark kaynak kaplama yöntemiyle alaşımlandırılmıştır. Kaplama tabakası; optik mikroskop (OM), taramalı elektron mikroskobu (SEM), X-ışın difraktogramı (XRD) ve X ışını enerji dağılım spektrometresinden (EDS) faydalanılarak incelenmiştir. Optik mikroskop ve mikroyapı incelemeleri neticesinde, kaplama tabakası ile alt tabakanın birbirlerine metalurjik olarak bağlandığı ve yapıda ostenit (), (Cr,W)2B, Fe23(C,B)6, Cr7C3 ile Ni4B3 faz ve karbürleri belirlenmiştir. Kaplama tabakasının adhezyon aşınma direnci, yapıda mevcut karbür ve fazlardan dolayı, alt tabakaya göre oldukça yüksek değerde olduğu tespit edilmiştir. In this study, B4C-Ni-WC powder was been alloyed on the 304 stainless steel surface by using plasma transfered arc (PTA) weld surfacing process. Alloyed layer and interface were examined with optical microscope (OM), scanning electron microscope (SEM), and X-Ray diffraction (XRD) and energy dispersive spectograph. OM and SEM observations have been shown that the obtained coating had a smooth and uniform surface, as well as a metallurgical combination with the AISI 304 stainless steel substrate without cracks and pores at the interface. The austenite (), (Cr,W)2B, Fe23(C,B)6, Cr7C3 and Ni4B3 phase and carbides have been determined in the microstructure. The adhesive wear resistance of the coating layer is higher than the AISI 304 stainless steel substrate material due to the forming of hard carbides.