Papers by Author: Nuran Ay

Abstract: Fly ash is a waste of ferrochromium production which contains high amount of Cr2O3 and Fe2O3. In this study, fly ash was incorporate into pigment recipe for the purpose of coloring due to its high Cr2O3 and Fe2O3 content. Pigments were produced by using Cr2O3, Fe2O3, CoO and fly ash, added to glaze composition at different ratios (wt. 1-5 %). Glazes were applied on ceramic tiles and fired at 1145 °C/ 30 min. Glazed tiles were analyzed by using Autoclave, Harcourt and color measurement tests. Increasing of fly ash content in glaze, the color of glaze changed from brown to grey. The results of Autoclave and Harcourt tests of glazed tiles meet the requirement. This data shows that the fly ash could be used as color additives in glaze.

Abstract: Pressureless sintering of hexagonal boron nitride (BN) with and without additives was performed using a powder which was previously nitrided at 900oC and then heat treated at 1400oC. Sintering additives were B2O3 (2, 4, 6 wt %) and Y2O3 (2, 4, 6 wt %) and sintering temperatures was 1900oC. Sintered samples were characterized by XRD, SEM, micro hardness, density and mercury porosimeter measurements. Maximum density values of samples were 1.56 g/cm3 without additives and 1.63 g/cm3 with additives. Hardness values of samples were found to improve with the presence of additives.