Investigation of parameters influence on optical properties of silicon glasses

1. microCAD 2004 Investigation of parameters influence on optical properties of silicon glasses Paróczai Csilla1, Dr Gömze A. László2 undergraduate, senior lecturer University of Miskolc, Department of Ceramic and Silicate Engineering

2. Goals • Our goal is reduce the number of these defects • The quick and exact determination of the defects

3. Glass • Amorf • Phisically homogeneous • Raw materials • Quarts sand SiO2 • Limestone CaCO3 • Dolomit CaCO3*MgCO3 • Feldspar R2O*Al2O3*SiO2 • Alumina Al2O3 • Soda Na2CO3 • Natrium-szulfatNa2SO4 • Coke • Cullet

4. Glass defects • Glassy unhomogeniticy (cord, knot) • Crystal or opaque bubble (stone, metal, crystal) • Air bubble (blister, bubble) • Cranny

5. Cause of the defects • Inadequate rawmaterial • Inadequate melting parameters • Substantial evaporation • Irregularity in the flowing glass • Contact of glass with the wall of the furnace

6. Methods are adopted to identify stones in glass. • Visual or magnifier observation • Methods using an electron-ray probe micro analyzer • Identification by chemical analysis • Identification by spectro analysis

7. SiO2 stones in the glass • Cause: • Cristallization • The silica brick corrodes and refractory material get into the glass • Unmelted quarts sand in the melting

8. Tridimit • Forceful stress lines • Cause: • Inadequate melting of the quarts sand

9. Kristobalit • Cause: • The silica brick corrodes and refractory material get into the glass

10. Al2O3-SiO2stones • Korrundum • The defect puport a lot of Al • Cause: • Polluted cullet

11. Cirkon Cause Corrosion of the furnace Al2O3-ZrO2-SiO2stones

12. Bubbles Top tin Other defects

13. Identification by polarization microscope When defect is reduced by glass, it loses O2. Thus this O2 meets with carbon and CO2 formes Experiment Method

14. Electron microprobe X-ray analyzer Jeol Superprobe 733 Thin carbon film High vacuum We examined two different zone of glass which are the metallic silica and the surrounding glass. Identification by EDX-microanalyses

15. This zone contains metallic pollutant such as Fe, Ti, Mn, Cu. Probably the cause of this defect is the polluted basic material. These defects could be reduced by using metal detector. 1. Zone Measurements and results

16. Mass and atomic percent of the elements of the glass

17. Measurements and results • Pure glass can be seen because the examined material contained only Si 2. zone

18. Conclusion • It is important to particle daily training for the eye to distinguish characteristics and optical properties peculiar to each kind of stone minerals may lead to the implementation of irrelevant countermeasures, and it is therefore essential to correctly identify stone minerals and of surmising the causes of their occurrence.

19. Thank you for attention.