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THE EFFECT OF NUCLEATING AGENT (ZrO2) ADDITION ON CRYSTALLIZATION BEHAVIOUR, MACHINABILITY OF POTASSIUM MICA AND FLOURAPATITE CONTAINING GLASS CERAMICS AND BIOACTIVITY CHARACTERIZATION In the first stage of the experimental studies, glass compositions having 3:7 weight ratio of flourapatite to potassium mica with different amount of nucleation agent (ZrO2) were prepared and melted at proper temperatures. Differential thermal analysis (DTA) and X-Ray diffraction (XRD) methods were applied in order to determine glass transition and crystallization temperatures and characterize phase precipitation sequence and identify phases. According to the DTA and XRD results, heat treatment programmes of glass-ceramic production were determined. In the second stage of the experimental studies, disc and cylindrical shaped samples were prepared to determine the microstructural and mechanical properties in terms of microhardness and machinability. Heat treatment methods were applied to the glass specimens in order to make microstructural characterization by using scanning electron microscope (SEM) and microhardness test for determining hardness values of the specimens and according to the obtained results, machinability test was applied by drilling. In order to investigate the bioactivity of the obtained glass-ceramics, samples were characterized by in-vitro characterization in simulated body fluid (SBF). The thin film X-Ray Diffraction (TF-XRD) analysis was used to investigate the phases which were precipitated on the surfaces of the specimens. Microstructure analysis of the surfaces was made by scanning electron microscope (SEM). The molecular bonding characterization was applied by using Fourier Transform Infrared Spectrometer (FTIR). |
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