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  • Küçük Resim
    Öğe
    A comparative study about production of vanadium carbide via self propagating high temperature synthesis and reduction
    (2024) Buğdaycı, Mehmet; Öncel, Levent; Alkan, Murat; Turan, Ahmet; Çınarlı, Umay
    Vanadium carbide is important for industrial applications because of its high hardness, high temperature resistance, high chemical, and thermal stability. It is generally obtained from the reaction between V and C powders at a high temperature ranging from 1100 to 1500°C. Investigations on these high strength, high abrasion resistant, hard materials have been intensified in recent years and consequently, significant improvements have been achieved. In this study, VC alloys are produced with low cost processes, by reducing the oxides of their components by SHS methods and ball mill-assisted carbothermal reduction. In the experimental stage, V2O5 was used as oxidized Vanadium source, Cblack as carbon source, magnesium and Cblack as reductant. In the study, VC powders were synthesized by two different methods and optimum production conditions were determined. Furthermore, the effect of different stoichiometric charge components and the effect of experiment durations were realized by X-ray diffraction, HSC Chemistry, and SEM analyses for different reductants.
  • Küçük Resim
    Öğe
    Effects of reductant type on the combustion synthesis of NiB
    (Elsevier, 2021) Odabaş, Ömür Can; Buğdaycı, Mehmet; Kan, Selçuk; Turan, Ahmet; Yücel, Onuralp
    Ni-B intermetallic alloys are important filler materials which are used in brazing applications. Carbothermic and aluminothermic synthesis routes are main methods to produce NiB. Carbothermic synthesis is carried out in electric arc furnaces and consumes high amount of energy whereas aluminothermic synthesis mainly uses its own reaction energy. Thus, via aluminothermic synthesis, the consumption of energy drops. Aluminothermic synthesis is a sub-group of combustion synthesis methods and, its name is based on the Al which is used as reductant in reactions. In the present study, aluminothermic synthesis conditions of NiB (mainly containing 15% B by wt.) were investigated for increasing B2O3 stoichiometry in reactants. Moreover, some experiments were conducted to understand the magnesiothermic synthesis conditions, as an alternative reductant. Results were compared to each other and to thermochemical simulations which were carried out by using HSC Chemistry 6.12 and FactSage 7.1 softwares. Chemical analysis, SEM-EDS and XRD were the main techniques to characterize raw materials and the products. Increasing B2O3 stoichiometry and the use of the Mg as reductant positively affected the chemical content of obtained NiB phases although metal recovery yields were lower for magnesiothermic experiments than that of aluminothermic experiments. For instance, in the magnesiothermic experiment carried out with 100% B2O3 stoichiometry, the obtained metallic fraction consisted of 84.2% Ni, 15.1% B and 0.1% Mg.