Mühendislik Fakültesi

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Browsing Mühendislik Fakültesi by Author "BUGDAYCI, MEHMET"

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    Corrosion behaviour of hydroxyapatite coatings on AZ31 and AZ91 magnesium alloys by plasma spray
    (JOURNAL OF CERAMIC PROCESSING RESEARCH, 2021-02-02) BUGDAYCI, MEHMET; BASLAYICI, SERKAN; MAHMUT ERCAN, AÇMA
    In the scope of this study, AZ31 and AZ91 magnesium alloys are to be coated with hydroxyapatite by plasma spray to be used as biodegradable implant material and their in-vitro corrosion behaviors are to be examined. There are a number of researches on the production of biodegradable cortical screws and plates used in orthopedic surgery in last decade. The advantage of biodegradable implants is that they do not need to be surgically removed. Moreover, the elastic modulus and the mechanical properties of magnesium are relatively close to those of the human bone, and this prevents the phenomenon of the human bone named “stress shielding. During this study, the hydroxyapatite coating processes, characterizations and corrosion behaviors of AZ31 and AZ91 will be examined. The aim of this work is to determine the optimal coating conditions for magnesium alloys for biodegradable implants. As a result of the plasma spray coating, the corrosion rate has decreased from about 1.2 mm/year to 0.4 mm/year.
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    Effects of binding agents in the production of SiC ceramic foam filters with replica method
    (JOURNAL OF CERAMIC PROCESSING RESEARCH, 2021-10-01) BUGDAYCI, MEHMET; BARAN, GİZEM
    In this study, casting filter production parameters were investigated by coating SiC with superior mechanical and chemical properties on polyurethane sponge. Many methods in which SiC filters are produced have been researched and considering its simple applicability, the replication method has been chosen as the production method. In the experiments, polyurethane sponges with different porosities were coated with varying proportions of water, bentonite, gum arabic and SiC, and then subjected to pyrolysis and sintering. The characterization of the samples was carried out by weight loss, compression test, Archimedes scale and SEM methods. According to the test results, the highest weight loss was obtained with 46% by adding 30 mL of water into 30 ppi polyurethane sponge. In the sintering tests, the highest strength was obtained with the value of 472 kPa in the experiment performed at 1,450 ºC. The same sample gave the optimum result with a density of 3.101 g/cm3 and porosity of 1.24%. At the end of the study, the samples produced successfully were used in the real casting process and it was observed that they were effective in filtering..
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    Hydrometallurgical Nickel and Cobalt Production From Lateritic Ores: Optimization And Comparison Of Atmospheric Pressure Leaching And Pug-Roast-Leaching Processes
    (ACTA METALLURGICA SLOVACA, 2021-02-02) BUGDAYCI, MEHMET; ÇOBAN, OZAN; BAŞLAYICI, SERKAN; MAHMUT ERCAN, AÇMA
    Corresponding to the technological developments, production and consumption of nickel have increased greatly over time due toits unique mechanical and chemical properties. Therefore, the production of nickel will always keep its importance. The availability of laterite ores, which are oxide type ores, is 86% of the nickel reserves on the Earth, and the processes used in the production of nickel from sulphidetype ores have negative environmental effects. Therefore, recovery of nickel from lateritic ores has become increasingly important in recent years. In this study, the aim was to determine the optimum parameters of nickel and cobalt produc-tion from limonite type lateritic nickel ores, which were taken from Manisa Caldag region of Turkey, using atmospheric pressure sulfuric acid leaching and pug-roast-leach process. When the results obtained in these processes were compared, it was found that the Ni leaching efficiency is nearly 8% higher and iron leaching efficiency (contamination) is nearly 4% lower in the pug-roast-leach process. Furthermore, the pug-roast-leach process was completed in 33% lower time compared to the atmospheric pressure sulfuric acid leaching process.