Yazar "Qader, Ibrahim Nazem" seçeneğine göre listele

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    Effects of heat treatment temperatures on phase transformation, thermodynamical parameters, crystal microstructure, and electrical resistivity of NiTiV shape memory alloy
    (Springer, 2020) Kok, Mediha; Al-Jaf, Ahmed Omar Ali; Cirak, Z. Deniz; Qader, Ibrahim Nazem; Ozen, Ecem
    Changing physical property of NiTi shape memory alloy by adding new element and heat treatment technique has become interesting in the last decades. In this study, equiatomic NiTi alloy was doped by 1 and 5 atomic percentages of vanadium element. For each case, heat treatment was accomplished for 873, 973, 1073, and 1173 K, and its effect on phase transformation temperatures was analyzed by differential scanning calorimetry. Crystal structure and chemical compound found in XRD pattern showed the different situation for each case, e.g., TiO2 appeared in heat-treated samples, whereby the intensity of peaks varied by changing the temperature of heat treatment. In NiTi-5V alloy, each enthalpy, entropy, Gibbs free energy, and elastic energy were decreased by increasing heat treatment temperature, while grain size of the alloy extended with respect to non-heat-treated sample. Electrical resistivity of the alloys was measured as a function of temperature, which was increased by increasing vanadium composition and heat treatment temperature.
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    The effects of substituting Sn for Ni on the thermal and some other characteristics of NiTiSn shape memory alloys
    (Springer, 2021) Qader, Ibrahim Nazem; Kok, Mediha; Cirak, Zehra Deniz
    In this study, the thermal stability and phase transformation of Ni50-xTi50Snx (x = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 at%) SMAs have been investigated. Some thermal, mechanical, and microstructural characteristics were measured using DSC, Vickers microhardness, XRD, and SEM-EDX devices. Calculations, such as grain size and entropy change, were also performed based on the DSC results. It is found that by increasing the amount of Sn in NiTiSn alloy, fragmentation has occurred in the alloy, which may be due to the high concentration of Sn and Ti in the grooves. Furthermore, the microhardness and grain size are in harmony, i.e., the microhardness of the alloys was influenced by the grain size. Additionally, martensite and austenite peaks were shifted to the lower temperature by increasing the cycling process, while the rate of shifting increased generally by adding more Sn element into the alloy.
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    IN VITRO STUDY, CORROSION, AND THERMAL OXIDATION BEHAVIOR OF WIRE-SHAPED NITISN SHAPE MEMORY ALLOY
    (World Scientific Publ Co Pte Ltd, 2021) Qader, Ibrahim Nazem; Kok, Mediha; Cirak, Zehra Deniz; Pekdemir, Mustafa Ersin; Saydam, Sinan; Aydogdu, Yildirim
    The development of NiTi-based shape memory alloys (SMAs) for some medical applications has been limited by releasing Ni element into the organic tissue. In this study, Ni47Ti50Sn3-wire (at.%) SMA was produced using the arc-melting technique, and the alloy was subjected to non-isothermal processes. Some characteristics of the alloys, such as oxidation behavior, corrosivity, and in vitro study in simulated body fluid and physiological solution at body temperature, were investigated. The corrosion rate of the as-casted alloy was lower than the equiatomic-NiTi alloy found in the literature. The estimated ICP-MS results showed that the release of alloying constituents into the solutions is in accordance with the standards.
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    Investigation of Electrochemical and Thermal Properties of Ti50Ni40-xZr10Nbx SMAs
    (Springer, 2024) Abdullah, Shakhawan Salih; Balci, Esra; Qader, Ibrahim Nazem; Dagdelen, Fethi
    Titanium and its alloys have already been widely used as implant materials due to their outstanding mechanical characteristics, thermal properties, and biocompatibility. In this study, Ti50Ni40-xZr10Nbx (x = 1, 3, 5 at.%) shape memory alloys (SMAs) with a constant atomic percentage of Ti and Zr were investigated. For investigation of the structural properties of produced SMAs, scanning electron microscope (SEM-EDX) analysis, optical microscope (OM) images, and x-ray diffraction (XRD) pattern were taken. B2, B19', beta-Nb, and Ti2N phases were detected in all alloys. In SEM-EDX and OM research, it was determined that beta-Nb phase increased in dendritic structure as the Nb ratio increased. For the biocompatibility levels of alloys, the corrosion test method was carried out with the potentiodynamic test, which is one of the electrochemical methods. Tafel test and electrochemical impedance spectroscopy in a simulated body fluid (SBF) showed that the Nb additive increased the corrosion resistance of the alloy. Phase transformation temperatures (PTTs) of these alloys were investigated by using differential scanning calorimetry (DSC) measurements. In DSC research, it was determined that the alloys have a shape memory effect (SME), and the PPTs of the alloys decreased as the Nb ratio increased.
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    Synthesis and characterization of NiFe2O4 piezoelectric nanoparticles: a comprehensive study on the influence of natural surfactants, kinetics, and thermodynamics
    (Springer, 2024) Babakr, Karukh Ali; Qader, Ibrahim Nazem; Amiri, Omid; Ozabaci, Murat; Aspoukeh, Peyman; Hamad, Samir Mustafa
    Using piezoelectric nanoparticles created with natural surfactants to remove dyes from water is a promising, environmentally friendly approach with potential benefits in sustainability, efficiency, cost-effectiveness, and innovation in water treatment technologies. This study investigates the influence of natural surfactants on the synthesis of hydrothermal-based Ni ferrite nanoparticles designed for dye removal. Three fruit juices-grape, orange, and peach-were employed in the preparation process, and their properties were scrutinized through X-ray diffraction (XRD), scanning electron microscope (SEM), and Energy-dispersive X-ray spectroscopy (EDAX). The research also explores the effects of varying time and temperature parameters on dye removal. Results indicate that Ni-ferrite nanoparticles synthesized with grape juice exhibit enhanced efficacy in degrading crystal violet dye. Moreover, the morphology of these nanoparticles diverges from those produced through alternative methods documented in the literature. The study's findings suggest that the degradation of Crystal Violet (CV) by a NiFe2O4 catalyst through piezoelectric means adheres to pseudo-second-order kinetics. Thermodynamic analyses reveal that CV piezo degradation is an endothermic process. The presence of nearly spherical nanoparticles in all samples is accompanied by the remarkable identification of bar-shaped crystalline particles with piezoelectric properties with a length of around 3 mu m and a diameter of 300 nm in samples synthesized with grape juice. This unique morphological characteristic, which has not been previously reported for nickel ferrite, represents a novel finding. In conclusion, we posit that natural surfactants, exemplified by grape juice, exert a substantial influence on the microstructure of nanoparticles, thereby influencing their potential applications.