Sands obtained from the porphyry extg. process, of compn. SiO2 72.40, Al2O3 13.85, K2O 4.60, Na2O 3.00, Fe2O3 2.15, CaO 1.30, MgO 0.84, TiO2 0.20% and loss on ignition 2.06% were mixed and then melted with TiO2 (4%) and MgO (5-15%) to prep. fine-grained glass-ceramics. The devitrification process was studied by DTA, x-ray diffraction and SEM. After heat treatment MgSiO3 and TiO2 crystals form. By increasing the MgO content, the crystallinity percentage increases, approaching the max. amt. stoichiometrically obtainable from the oxides added, the devitrification rates are speeded up, and the microstructure developed is increasingly finer.
Influence of TiO2 and MgO on glass ceramics formation from porphyritic sands mixture / P. G., Orsini; P., Scardi; G., Gialanella; A., Tomasi; Branda, Francesco. - In: MATERIALS ENGINEERING. - ISSN 0025-5319. - ELETTRONICO. - 3:(1992), pp. 77-83.
Influence of TiO2 and MgO on glass ceramics formation from porphyritic sands mixture
BRANDA, FRANCESCO
1992
Abstract
Sands obtained from the porphyry extg. process, of compn. SiO2 72.40, Al2O3 13.85, K2O 4.60, Na2O 3.00, Fe2O3 2.15, CaO 1.30, MgO 0.84, TiO2 0.20% and loss on ignition 2.06% were mixed and then melted with TiO2 (4%) and MgO (5-15%) to prep. fine-grained glass-ceramics. The devitrification process was studied by DTA, x-ray diffraction and SEM. After heat treatment MgSiO3 and TiO2 crystals form. By increasing the MgO content, the crystallinity percentage increases, approaching the max. amt. stoichiometrically obtainable from the oxides added, the devitrification rates are speeded up, and the microstructure developed is increasingly finer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
