Crystallization behaviour of glasses produced from fly ash

Erol M., KUCUKBAYRAK S., ERSOY-MERICBOYU A., Ovecoglu M. L.

Journal of the European Ceramic Society, cilt.21, sa.16, ss.2835-2841, 2001 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 21 Sayı: 16
  • Basım Tarihi: 2001
  • Doi Numarası: 10.1016/s0955-2219(01)00221-7
  • Dergi Adı: Journal of the European Ceramic Society
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.2835-2841
  • Anahtar Kelimeler: crystallization kinetics, fly ash, glasses, glass ceramics, hardness, waste materials, DIFFERENTIAL THERMAL-ANALYSIS, CRYSTAL-GROWTH, KINETICS, NUCLEATION, CERAMICS, VITRIFICATION, PARAMETERS, SLAG
  • İstanbul Teknik Üniversitesi Adresli: Evet

Özet

The crystallization behaviour of fly ash based glass samples annealed at 600°C for 2 and 10 h was investigated by DTA, XRD and SEM. On the basis of DTA, nucleation experiments of two glass samples were carried out at 680 and 687°C for 5 h and crystallization experiments were performed at 924 and 892°C for 20 min. The Avrami constant for both glass samples was calculated as 4, which indicates bulk crystallization, predicted by the Ozawa equation. Using the modified Kissinger equation, activation energies of crystal growth were determined as 318 and 318 and 312 kj/mol for samples annealed at 2 and 10 h, respectively. Single peak analysis technique proved that the activation energy is independent of DTA heating rate. SEM observations indicated that the produced glass-ceramic samples have fine grained microstructure. The crystallized phase was identified as diopside [Ca(Mg,Al)(Si,Al)2O6] by X-ray diffraction analysis. The results of Vickers microhardness tests showed that the hardness values of the produced glass-ceramic samples decreased with the increase in holding time at the annealing temperature. © 2001 Published by Elsevier Science Ltd. All rights reserved.