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- MakaleAçık Erişim2026Scopus SJRQ2Comparative Microstructural, Mechanical, and Tribological Evaluation of Cu Matrix Composites Reinforced with B4C, B, Cr, Co, Al2O3, and Graphite via Powder Metallurgy
Macit, Cevher Kursat; Gürgenç, Turan; Aksakal, Bunyamin; Aslan, Naim
Copper and its alloys are widely used in electrical, automotive, aerospace, and energy applications because of their excellent thermal and electrical conductivity. However, the low hardness and poor wear resistance of pure Cu limit its use under tribologically demanding sliding conditions. In this study, Cu matrix composites reinforced with 1 wt.% boron carbide (B4C), boron (B), chromium (Cr), cobalt (Co), alumina (Al2O3), and graphite (Gr) were fabricated by powder metallurgy and comparatively evaluated under identical processing and testing conditions. Phase constitution and microstructural characteristics were analyzed by XRD, SEM, and EDS, while mechanical and tribological behavior was assessed by Vickers hardness and dry sliding wear tests. All reinforcements improved the hardness of the Cu matrix compared with unreinforced Cu. The hardness increase followed the order Cu–B4C (68.91%) > Cu–B (66.43%) > Cu–Gr (63.97%) > Cu–Al2O3 (61.79%) > Cu–Cr (42.69%) > Cu–Co (36.04%). Dry sliding wear tests, performed under a 10 N normal load, 0.05 m s−1 sliding speed, and 1000 m sliding distance against a 316L stainless-steel ball, showed that all reinforced composites exhibited lower mass loss and more stable sliding behavior than pure Cu. Among all samples, Cu–B4C displayed the best wear performance, with a 154.8% improvement in wear resistance relative to pure Cu. SEM analysis of the worn surfaces revealed that reinforcement addition reduced severe plastic deformation, groove formation, and delamination, leading to a more stable wear regime. Graphite- and boron-containing composites benefited from interfacial lubrication and contact stabilization, whereas B4C and Al2O3 improved wear resistance through rigid-particle strengthening and enhanced load-bearing capacity. By comparing ceramic, metalloid, metallic, oxide, and solid-lubricating reinforcements at the same low addition level and under identical processing and testing conditions, this study provides a reinforcement-selection framework for Cu-based composites requiring improved hardness and dry-sliding durability.
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İncele - MakaleAçık Erişim2025Scopus SJRQ2Investigation of anticorrosive and antibacterial properties of electrochemically modified AISI430 steel surfaces; [Elektrokimyasal yöntem ile modifiye edilmiş AISI430 çelik yüzeylerin antikorozif ve antibakteriyel özelliklerinin incelenmesi]
Açar, Gülistan; Cihangir, Salih; Omaç, Basri; Aydoğdu, Hacı Mehmet; Oflaz, Mücahit
Both pharmacological and material-based approaches aim to slow bacterial evolution toward resistance. In this context, imparting specific antibacterial properties to materials is essential. Traditionally, alloying was a method to equip entire metals with antibacterial features, such as incorporating small amounts of copper (Cu) and/or silver (Ag). However, due to the high cost and inherent limitations of alloying, surface modification processes have gained prominence. Recent antibacterial studies on copper have led to the application of Cu(Ag) electrochemical coatings on AISI430 steel surfaces. This study aims to combine copper’s antibacterial properties with enhanced corrosion resistance and surface hardness. The coatings were deposited using deep eutectic solvents, known for their environmentally friendly properties, followed by potentiodynamic analysis. Microstructural and phase distribution characteristics were examined through SEM-EDS analysis, while surface roughness was analyzed using profilometry. Transitioning from micro-disc electrodes to macro-scale AISI430 substrates, Cu(Ag) films containing 16% Ag demonstrated nanoscale roughness, approximately double the hardness, and superior corrosion resistance compared to conventional copper surfaces. Antibacterial tests compared the coated surfaces with untreated AISI430 steel. Results showed that Cu(Ag)-coated surfaces exhibited improved antibacterial properties. This study shows how Cu(Ag) electrochemical coatings can be used to make surfaces that are antibacterial, long-lasting, and resistant to corrosion.
- MakaleAçık Erişim2023Scopus SJRQ3Production of SBS Reinforced Polyester Composite: Characterization of Physical and Chemical Properties
Şahal, Hakan; Aydoğmuş, Ercan
In this study, dissolved styrene butadiene styrene (SBS) copolymer is homogeneously reinforced into orthophthalic unsaturated polyester (UP) resin. Polyester composite production is carried out with the help of methyl ethyl ketone peroxide (MEKP) and cobalt octoate (Co Oc) catalysts. The density, Shore D hardness, thermal conductivity coefficient, thermal stability, morphological surface structure, and chemical bond structure of the obtained composite have been examined. According to the results, SBS reinforcement decreases the density of the composite and increases the thermal conductivity coefficient. The addition of SBS at different weight ratios (1%, 3%, 5%, 7%, and 10% w/w) reduces both the hardness and thermal stability of the polyester composite. According to the test and analysis results, 5 wt.% SBS reinforced polyester composite production is determined as the optimum ratio. 7 wt.% and above SBS reinforcement negatively affect the physical and chemical properties of the obtained composite. For example, when 10 wt. % SBS reinforced composite is examined by scanning electron microscope (SEM), and irregular pores are observed in the surface morphology. Also, it is understood by Fourier transform infrared spectroscopy (FTIR) that there is a physical interaction between SBS and polyester and that no chemical bond is formed. The thermal decomposition behavior of the composite has been determined according to the decrease in the activation energy. As SBS ratio increases, it is understood that the thermal stability of the product obtained with the decrease in the activation energy of the polyester composite weakens.
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İncele - Yüksek Lisans TeziAçık Erişim2022Nadir toprak elementleriyle katkılandırılmış borat camların fiziksel ve radyasyon zırhlama özelliklerinin incelenmesi
İlyas İzgüden
Bu çalışmada Ülkemizde yer alan zengin bor madeni rezervinin daha verimli kullanılması amacıyla ana maddesi bor oksit olan ve içerisine yine ülkemizde ham madde olarak bulunan ve yeni keşifler ve incelemelere konu nadir toprak elementleri katkılanarak hazırlanan ve kurşun katkılı camlara alternatif olabilecek ve yüksek teknoloji ürünlerinde (Akıllı cihaz ekranları, uzay ve sağlık teknolojileri gibi) kullanılabilecek yeni nesil radyasyon kalkanlayıcı camlar üretmektir. Üretimi yapılan ürünlerin öncelikle XRD yöntemi ile faz tanımlaması yapılmış ve numunelerin amorf yapısına sahip cam olduğu belirlenmiştir. Üretilen numunelerin FTIR yöntemi ile kimyasal bağları ve moleküler yapıları araştırılarak düzgün bağlar oluşturan camlar olduğu belirlenmiştir. Elde edilen numunelerin UV-Vis Spektroskopisi yöntemi ile ışık geçirgenliği ve soğurma spektrumları belirlenerek normal cam karakteri gösterdiği belirlenmiştir. Camların camsı özelliklerinin iyi sonuçlar verdiği tespit edilmiş ve mekanik özelliklerden yoğunluk, sertlik, kırılma toklukları ve gevreklikleri incelenmiş ve sonuçları değerlendirilmiştir. Cam örneklerinin radyasyon zırhlama ölçümleri Atatürk Üniversitesi Fen Fakültesi Fizik Bölümü Prof. Dr. Wolf Weyrich Yüksek Enerji Spektroskopisi Laboratuvarı'nda bulunan deney düzeneği kullanılarak yapılmış ve cam örneklerinin kurşun katkılı camlara alternatif olabilecek seviyede radyasyon kalkanlama yaptığı belirlenmiştir. Bu çalışmanın amacı yapılan nadir toprak elementleri katkılı borat camlarda radyasyon zırhlamanın yanı sıra mekanik ve fiziksel özelliklerinin iyileştirilmesinde yardımcı olacak bir yayın (Tez) oluşturarak bilimsel çözümler sunmaktır.
- MakaleYalnız künye2016Scopus SJRQ3Characterization of hot pressed CuAl-TiC composites with different TiC grain sizes
Islak, S.; Çelik, E.; Kir, D.; Özorak, C.
In this study, the CuAl-TiC composite materials were produced using hot pressing process. Effect of TiC grain size (0.2, 4 and 20 mu m) on some properties of these materials was investigated experimentally. Production of CuAl-TiC composites was carried out under pressure of 35 MPa, at 700A degrees C, and for a sintering time of 5 minutes. SEM-MAP studies showed that the TiC grains were relatively homogeneously distributed in the CuAl matrix. Microstructure analysis revealed that the composite materials consist of Cu, Al, Cu9Al4, CuAl2 and TiC phases. With the decreasing of TiC grain size, the hardness, transverse rupture strength, relative density and sintered density of composites increased.
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