Nucleation in 49Na(2)O.49SiO(2).2ZrO(2) and 47Na(2)O.51SiO(2).2ZrO(2) glass
es were investigated by differential thermal analysis measurement after hea
t-treatments at 400-580 degrees C for 0-123 h. The addition of ZrO2 increas
ed crystallization peak temperature, T-C, and shifted the temperature, T-ma
x, at which nucleation rate is maximum to higher temperatures. The relation
ship between the number density of nuclei formed during the heat-treatment
and Te was calculated. The variation of the number density of nuclei was ob
tained from the comparison between the calculated Te and the observed Te as
a function of heat-treating time. The transient time for nucleation of 47N
a(2)O.51SiO(2).2ZrO(2) glass was 42 h at 430 degrees C. From these results,
we found ZrO2 has an effect on the nucleation kinetics of Na2O-SiO2 glass.
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