Browsing by Author "Uzun, A."

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    Web of Science
    Electrochemical, mechanical, and antibacterial properties of the AZ91 Mg alloy by hybrid and layered hydroxyapatite and tantalum oxide sol-gel coating
    (2023.09.28) Albayrak, S.; Gul, C.; Emin, N.; Gokmen, U.; Karakoc, H.; Uzun, A.; Çinici, H.
    The corrosion and bacterial behavior of AZ91 magnesium alloy coated with sol-gel-deposited amorphous tantalum oxide and hydroxyapatite have been investigated. The objective was to assess the potential suitability of AZ91 for permanent prosthesis applications. The coatings were applied in layered and hybrid configurations and characterized using various techniques including X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive spectrometry, and drop analyses. The antibacterial properties were evaluated through interactions with Staphylococcus aureus and Escherichia coli strains. Mechanical properties and adhesion were determined via linear scratch tests, and electro-chemical corrosion tests were conducted in different media. The release of aluminum ions from the samples in Dulbec-co's Modified Eagle's Medium was monitored over 28 days. The findings revealed that the amorphous tantalum oxide coating, particularly in combination with hydroxyapatite, improved antibacterial properties and positively influenced corrosion and scratch resistance. The layered and hybrid coatings demonstrated the highest corrosion resistance. The release of aluminum ions remained within acceptable levels in the tested medium. Overall, the study provides valuable insights into the potential of sol-gel coatings on AZ91 for prosthetic applications, considering antibacterial behavior, corrosion resistance, and aluminum release.
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    Web of Science
    Mechanical and Electrical Properties of Graphene Nanosheet Reinforced Copper Matrix Composites Materials Produced by Powder Metallurgy Method
    (2023.01.01) Albartouli, A.B.M.; Uzun, A.
    This study investigated the mechanical and electrical properties of copper matrix composite materials reinforced with graphene nanosheets. The composite materials were produced using the powder metallurgy method, with several weight percentages graphene nanosheets (0, 0.5, 1 and 1.5) added to the copper matrix powders. The mixed powders were compacted unidirectionally in a steel mold at different pressures (500, 600 and 700 MPa) and sintered in an argon atmosphere at different temperatures (850, 900 and 950 degrees C). Furthermore, the sintered samples were subjected to microstructure analysis, hardness and electrical conductivity measurements. The results showed that the microstructure exhibited porosity and agglomeration with increasing amounts of graphene nanosheets, resulting in a decrease in relative density up to 87.4%. The highest electrical conductivity was 76.59 IACS (0% GNS-500 MPa-950 degrees C), while the lowest was 43.49 IACS (1.5% GNS-500 MPa-850 degrees C). The addition of graphene nanosheets resulted in a relative increase in hardness of up to 1%.