analogous coefficients and uncover some generalized correlations between glass-forming ability (GFA) and glassstability (GS).
Glass-forming ability and GS
Glass is a specific matter reflecting its original liquid makeup and can
Authors:J. Zhu, H. Jin, D. Dong, D. Qiang, and F. Ma
The glass formation and devitrification of GaF3-based glasses were studied by differential scanning calorimetry. A comparison of various simple quantitative methods to assess
the level of stability of multicomponent fluoride glass systems is presented. Most of these methods are based on critical
temperatures. In this paper a new parameter kb(T) is added to the stability criteria. The stability of several GaF3-based glasses were experimentally evaluated and correlated with the activation energies of crystallization via this new kinetic
criterion and compared with those evaluated by other criteria.
The present paper reports on the effect of MoO3 on the glass transition, thermal stability and crystallization kinetics for (40PbO–20Sb2O3–40As2O3)100−x–(MoO3)x (x = 0, 0.25, 0.5, 0.75 and 1 mol%) glasses. Differential scanning calorimetry (DSC) results under non-isothermal conditions
for the studied glasses were reported and discussed. The values of the glass transition temperature (Tg) and the peak temperature of crystallization (Tp) are found to be dependent on heating rate and MoO3 content. From the compositional dependence and the heating rate dependence of Tg and Tp, the values of the activation energy for glass transition (Eg) and the activation energy for crystallization (Ec) were evaluated and discussed. Thermal stability for (40PbO–20Sb2O3–40As2O3)100−x–(MoO3)x glasses has been evaluated using various thermal stability criteria such as ΔT, Hr, Hg and S. Moreover, in the present work, the Kr(T) criterion has been considered for the evaluation of glass stability from DSC data. The stability criteria increases with
increasing MoO3 content up to x = 0.5 mol%, and decreases beyond this limit.
Glasses with the composition Li2O·2SiO2·nTiO2 and Li2O·2SiO2·nZrO2, where n=0, 0.03, 0.062, 0.1, were prepared and the onset and peak temperatures have been determined by DTA. From these characteristic
temperatures, the kinetic parameters describing the nucleation and crystal growth have been obtained by isoconversional methods.
The kinetic parameters have been used for the calculation of nucleation and crystal growth times for individual glasses so
determining the order of glass stability at reheating. The stability of glasses increases with the content of TiO2 or ZrO2 where the increase is higher for ZrO2. Within the concentration range under study, the increase of both times with the metal oxide concentration is quadratic.
It has been discussed that the crystallization kinetics does not obey the Arrhenius law and, therefore, when using the evaluation
methods based on this law, the results should not be extrapolated outside the temperature range of the measurements.
Authors:S. Lendvayová, K. Moricová, E. Jóna, J. Kraxner, M. Loduhová, V. Pavlík, J. Pagáčová, and S. C. Mojumdar
). Several authors [ 8 , 9 ] suggested that the crystallization activation energy could also be used to evaluate the glassstability, but criteria based on the activation energy, or crystallization rate constants do not always fit with the actual
The values of thermal stability were established by relation: K H = ( T c − T g ∗ )/( T m − T c ); where K H is Hruby parameter of glassstability [ 10 ]. The compositional dependency K H of glassy samples is presented in Fig. 8 for both
obvious advantage of this method is that it can evaluate the glassstability over a broad temperature range other than at only one temperature such as T g or T p .
Bulk chalcogenide Sb x Ge 25− x Se 75 (0 ≤ x
Authors:P. Mošner, K. Vosejpková, L. Koudelka, and L. Beneš
temperature, T c , peak temperature, T p , flow temperature, T f , criterion of glassstability, T c − T g , of (100 − x )[0.5ZnO–0.1B 2 O 3 –0.4P 2 O 5 ]– x TeO 2 glasses and survey of crystalline products identified by XRD in the samples annealed at
lowest for 60B 2 O 3 –40Bi 2 O 3 , indicating that 60B 2 O 3 –40PbO is more thermally stable . It was previously reported that the higher Bi 2 O 3 content of the alloy, the lower its glassstability [ 25 – 27 ].