DTA at ≤590° was used to study nucleation and crystal growth in a 2Na2O.CaO.3SiO2 glass prepd. by melting anal. grade reagents at 1900° for 6 h. Internal crystn. occurred in the glass without any nucleating agent. The temp. of max. nucleation rate (500°) was very close to the glass transition temp. The effect of the surface area of samples and their thermal history on the crystn. mechanism was detd. The activation energy of crystal growth for quenched bulk samples and for previously nucleated ones was 104 and 107 kcal/mol, resp. The values were close to those obtained under isothermal conditions. Powd. samples were not suitable for DTA studies of nucleation and crystn. processes.
Nucleation and crystal growth in 2Na2O*CaO*3SiO2 glass. A DTA study / A., Marotta; Saiello, Silvana; Branda, Francesco; A., Buri. - In: VERRES ET RÉFRACTAIRES. - ISSN 0337-5676. - STAMPA. - 35:(1981), pp. 477-480.
Nucleation and crystal growth in 2Na2O*CaO*3SiO2 glass. A DTA study
SAIELLO, SILVANA;BRANDA, FRANCESCO;
1981
Abstract
DTA at ≤590° was used to study nucleation and crystal growth in a 2Na2O.CaO.3SiO2 glass prepd. by melting anal. grade reagents at 1900° for 6 h. Internal crystn. occurred in the glass without any nucleating agent. The temp. of max. nucleation rate (500°) was very close to the glass transition temp. The effect of the surface area of samples and their thermal history on the crystn. mechanism was detd. The activation energy of crystal growth for quenched bulk samples and for previously nucleated ones was 104 and 107 kcal/mol, resp. The values were close to those obtained under isothermal conditions. Powd. samples were not suitable for DTA studies of nucleation and crystn. processes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
