Influence of the heating rates on the correlation between glass-forming ability (GFA) and glass stability (GS) parameters

Abstract It is well known that some glass stability (GS) parameters which can be used to estimate glass-forming ability (GFA) are readily obtained by means of Differential Scanning Calorimetry (DSC) or Differential Thermal Analysis (DTA) experiments. In this work, the GS parameters proposed by Hruby (K H ), Weinberg (K W ), Lu & Liu (K LL ), Long et al. (K LX ) and Zhang et al. (K ZW ) were determined for the following silicate glasses: Li 2 O·2SiO 2 , BaO·2SiO 2 , Na 2 O·2CaO·3SiO 2 and 2BaO·TiO 2 ·2SiO 2 . Monolithic specimens of these glasses were placed in Pt–Rh crucibles and heated in air in a DSC furnace at different heating rates (ϕ = 2, 5, 10, 15, 20, 25 and 30 °C/min) from room temperature up to their respective melting temperatures. The results indicate that all the parameters under study vary significantly as a function of the heating rate, and that K H , K W and K LL increase with ϕ while K ZW and K LX decrease. To evaluate the reliability of these parameters in estimating GFA, they were correlated with the critical cooling rates ( R C ) calculated by the continuous cooling ( R CC ) and “nose” ( R CN ) methods using experimental data of steady-state nucleation and crystal growth rates, free energy per unit of volume, and viscosity of each vitreous material investigated. It was found that the correlation between the GFA ( R CC or R CN ) and all the parameters studied here persists, even if the changing of the GS parameters with the heating rates is taken into account.