Aslı ÇAKIR ARİANPOUR, Farzin ARİANPOUR, Behnam ALİ

Sodyum Silikoflorürün Mikroyapı ve Isıl Davranışlarının İncelenmesi

Sodyum silikoflorür, Na2SiF6'nın kimyasal formülü ile son zamanlarda seramik, metalurji ve kimya mühendisliği gibi çeşitli endüstrilerde birçok uygulama alanı bulan inorganik sentetik bir malzemedir. Bu tozun en önemli kullanımlarından bazıları opal cam-seramik, sırlar ve fritlerdir. Uygulama alanlarının gün geçtikçe artmasına karşı, literatürde sodium silikoflorür (SSF) ile ilgili sınırlı sayıda kaynak mevcuttur. Bu araştırmada, ticari bir sodyum silikoflorür tozunun ısıl davranış ve mikroyapı açısından karakterize edilmiştir. Termal analiz, hava atmosferinde 900 °C’de diferansiyel termal ve termo gravimetri eğrilerine göre araştırılmıştır. Mikroyapısal analizler, taneciklerin tane büyüklüğü ve morfolojisini incelemek için taramalı ve geçirimli elektron mikroskopları kullanılarak yapılmıştır. Sonuçlar, ticari sodyum silikoflorür malzemesinin, eşlik eden bir endotermik reaksiyonla havada 430-600 °C sıcaklık aralığında çözündüğünü göstermiştir. Mikroyapısal karakterizasyonlarla, incelenen SSF tozunun granüler morfolojisi, altıgen şekilli prizmaların ve ilgili gözeneklerin varlığına da açıklık getirmiştir.

Anahtar Kelimeler:

Sodyum silicoflorür, Karakterizasyon, Termal analiz, Elektron mikroskobu

Microstructural Study and Thermal Behavior of Sodium Silicofluoride

Sodium silicofluoride, with the chemical formula of Na2SiF6, is an inorganic synthetic material which recently found lots of applications in various industries such as ceramic, metallurgy and chemical engineering. One of the main important usages of this powder is in the production of opal glass-ceramics, glazes and frits. Despite the expansion of its applications, the properties of this material were not investigated deeply elsewhere. In this research, a commercial sodium silicofluoride powder was studied and characterized in terms of thermal behavior and microstructure. The thermal analysis was investigated according to the differential thermal and thermo gravimetry curves by heating the material up to 900 °C in air. The microstructural analyses were also performed using scanning and transmission electron microscopies to study the grain size and morphology of the particles. The results showed that this commercial sodium silicofluoride material is decomposed in the temperature range of 430-600 °C in air by an accompanied endothermic reaction. The microstructural characterizations were also clarified the granular morphology of the studied SSF powder, existence of the hexagonal shaped prisms and associated pores.

Keywords:

Sodium silicoflouride Characterization, Thermal analysis, , Electron microscopy,

PDF

___

Andreeva, V. & Fekeldjiev, G. (1986) Use of nonconventional raw materials in ceramic production. Ceramics International, 12, 229-235.
Arai, T. & Adachi, S. (2011) Mn-activated Na2SiF6 red and yellowish-green phosphors: A comparative study. Journal of Applied Physics, 110, 063514.
Ciavatta, L., Iijliano, M. & Porto, R. (1988) Fluorosilicate equilibria in acid solution, Polyhedron, 7 (18), 1773-1779.
Coyle, G. J., Tsang, T. & Adler, I. (1981) XPS studies of surface damages of transition metal fluorosilicates under argon ion bombardment. Surface Science, 112, 197-205.
Hattab, F. N. (1987) Direct determination of fluoride in selected dental materials. Dent. Mater., 3, 67-70.
Jeong, H. L. & Huh, Y.D. (2010) Synthesis of hexagonal prisms and hexagonal plates of Na2SiF6 microcrystals. Materials Letters, 64, 1816-1818.
Khan, M. S., Shahzadi, P., Alam, S., Javed, K., Shaheen, F., Naqvi, J. & Shahnaz, A. (2015) Development of heat resistant borosilicate glass doped with sodium silico fluoride compound. Journal of Chemistry and Materials Research, 4, 1, 13-18.
Kumar, M., Nani Babu, M., Mankhand, T.R. & Pandey, B.D. (2010) Precipitation of sodium silicofluoride (Na2SiF6) and cryolite (Na3AlF6) from HF/HCl leach liquors of alumino-silicates, Hydrometallurgy, 104, 304-307.
Smith, G. E. (1985) Toxicity of fluoride-containing dental preparations: A review. The Science of the Total Environment, 43, 41-61.
Toure, A. O., Keinde, D., Sambe, F. M., Joseph, M. & Diop C. G. M. (2017) Use of a fluoride waste in the raw mix for clinker manufacturing. American-Eurasian Journal of Scientific Research, 12, 1, 1-6.
Vanka, M. & Vachuska, J. (1980) Thermal decomposition of sodium hexafluorosilicate. Thermochimica Acta, 36, 387-391.
Yeo, B. E., Cho, Y. S.& Huh, Y. D. (2016) Synthesis and photoluminescence properties of a red-emitting phosphor K2SiF6:Mn4+ for use in three-band white LED applications, Optical Materials, 51, 50-55.