Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
Browse
2 results
Search Results
Master Thesis Effect of Arc Deposition and High Power Impulse Magnetron Sputter Coatings on the Performance of Tools for Machining Various Ferrous Materials and Ti6al4v Alloys(Izmir Institute of Technology, 2023) Nohuz, Mine; Davut, Kemal; Davut, Kemal; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this thesis, the performance of different coating techniques in machining various steels and Ti6Al4V is investigated. Currently, most of the carbide tools with the coating because of the tool life. In order to increase the productivity of the manufacturing processes and to use new materials, the research on the coating of cutting tools has been increased. Recently, the interest in physical vapor deposition has increased because the tool life is increased for many difficult-to-machine materials and difficult machining conditions. Two types of PVD coating were used in this work. The surfaces of the coated tools were examined under scanning electron microscope. The effects of cathodic arc deposition and high pulse magnetron sputtering on tool performance were investigated on various workpieces such as 4140 and CK45 steels, D2 tool steel (60HRC), GG25 cast iron and also on Ti6Al4V alloy. In the performance tests, the cutting forces were measured over a period of time and the wear patterns were recorded. The results indicate that HIPIMS coated tools perform better in operations where normal load is low and torsion forces are high. Those tools also work better in materials harder than 250 BHN. The better performance of HIPIMS coated tools were attributed to their less smooth and droplet free surfaces.Master Thesis Coating of La1-Xsrxco1 Films on Zirconia and Cgo (cerium Gadolinium Oxide) by Electrostatic Spray Deposition (esd)(Izmir Institute of Technology, 2010) Büyükkebabçı, Hande; Akkurt, Sedat; Akkurt, Sedat; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study preparation and characterization of coating of La0.6Sr0.4Co0.8Fe0.2O3-δ and La0.6Sr0.4Co0.2Fe0.8O3-δ materials on TZ-3Y (3 mol % doped yttria) and CGO (Ce0.9Gd0.1Oxide) ceramic electrolytes was studied. Electrostatic spray deposition (ESD) was used for depositing the coatings on ceramic electrolytes to develop a well bonded electrolyte-cathode material for potential IT-SOFCs (intermediate temperature solid oxide fuel cells) applications. Precursor solutions having La0.6Sr0.4Co0.8Fe0.2O3-δ or La0.6Sr0.4Co0.2Fe0.8O3-δ stoichiometry were prepared from various salts before being sprayed on a heated ceramic substrate which rapidly evaporated the solvent in the salts and the droplets struck and covered its surface. A high voltage was maintained to accelerate the droplets to high speeds. A coating with a minimal 1 µm of thickness was successfully produced. Effects of experimental parameters like the flow rate of the solution (0.3-1.5 ml/h), distance between the nozzle and substrate (15-45 mm), temperature of the substrate (250-375 °C), post heat treatment temperature (900-1300 °C) of the coated substrate and applied voltage on the quality of the coating were studied. Analytical tools like DTA/TGA, Scanning Electron Microscopy (SEM) and Xray Diffraction (XRD) were used to investigate the samples to check for the quality of the coating. Coating microstructures ranged from dense to porous depending on the deposition parameters. Sample with 30 mm distance and 0.7 ml/h of flow rate produced the best reticulated structure of the coating. No preferential landing effect was observed on any of the samples studied. Zirconia was not an effective substrate for formation of La0.6Sr0.4Co0.8Fe0.2O3-δ or La0.6Sr0.4Co0.2Fe0.8O3-δ. Cerium gadolinium oxide, however, was effective for La0.6Sr0.4Co0.8Fe0.2O3-δ but not for La0.6Sr0.4Co0.2Fe0.8O3-δ.