Crystallisation studies on site saturated lithium aluminosilicate (LAS) glass

Crystallization and sintering studies on an anomalous Li2O‐Al2O3‐SiO2 glass for making tunable thermal expansion ceramic

“…Such a low heating/cooling rate is extremely difficult in practical experiments. As per the results presented in reference 33 , prenucleated commercial LAS glass composition was found to have T k 427. 2 K and the corresponding k were found to be 7.23 × 10 -11 K/min.…”

“…Whereas, the addition of alkali ions facilitates scissoring of the silicate network and reduces thermal stability. Despite the presence of the surface sites in the powdered glass that can act as the heterogeneous site for nucleation, the average TS parameters determined for the present LAS composition are high than the one calculated for a commercial LAS glass presented in our previous work 33 and one presented for lithium silicate glasses. 31 The heating rate dependence of the transformation temperature follows a linear relation proposed by Lasocka (Eq.…”

“…The Lasocka plots corresponding to the heating rate dependence of T f , T c , T P are shown in Figure 2, and Lasocka relationships corresponding to these transformation temperatures were found to be The above set of equations can be used for selecting appropriate nucleation and crystallization temperature while designing a heat-treatment schedule for converting the glass into GC as we have implemented in our previous work. 33 The crystallization temperature and glass transition of the LAS glass were correlated using the following equation which was derived using the relations at Eq. 1, Here A f , A P , B f , and B P denote the constants in at Eq.…”

“…E and obtained here are comparable with established literature. 33 During crystallization, the activation energy was found to assume a constant value over a large range of crystallinity. 41 Assuming E constant, the mean value Avrami exponent, n was determined to 1.31 using the following relationship 37 for the x (volume faction crystallized) value 0.1 and 0.63.…”

“…The average values noted here were lower than those reported for a commercially important LAS glass. 33…”