3. Results and discussion
3.1. Thermal characterization of the frit
Fig. 1shows the thermal characterization results for the frit. From the linear thermal shrinkage plot (ΔL/Lo vs. T), the maximum sintering rate temperature (Ts) was approximately 7901C, and the temperature at the start of melting (Tm) was estimated to be approximately 10251C. From the DTA plot, the temperatures of the glass transition (Tg) and at the start of crystallization (Tx) were estimated to be approximately 540 and 7901C, respectively. The Tx−Ts difference indicates the interdependence of the sintering and the crystallization phenomena, i.e., greater values of Tx−Ts correspond to less interdependence [16,17]. In this study, the Tx−Ts difference equals zero, which indicates that it was difficult for the investigated composition to achieve high levels of densification. Moreover, the DTA plot depicts two onsets of crystallization: Tc1at approximately 8501C andTc2at approximately 9251C.