Study of Water Resistance of Fe2O3 Doped P2O5-ZnO-Bi2O3 Sealing Glass System

In order to strengthen the structure of the glass and ultimately improve its water resistance, P2O5-ZnO-Bi2O3 was doped with Fe2O3, which generated Fe ions in the phosphate-based glass. These ions constitute (P2O7)(-4) groups within the glass network. Structural analysis using Fourier transfer infrared spectroscopy indicated that P-O-P and Bi-O-P bonds decreased and Fe-O-P bonds increased, as a function of the Fe2O3 level. The thermal property analysis found that the softening point (T-s) and glass transition point (T-g) increased approximately as much as 60 and 105 degrees C, respectively, and the coefficient of thermal expansion decreased approximately by 25 x 10(-7) K-1. The contact angle was measured to quantify the wetting property. The contact angle increased from 42.6 degrees to 64.1 degrees with increasing levels of Fe2O3 at 850 degrees C. As an indication of water resistance, the weight loss of the 10 mol-% Fe2O3-doped glass was 0.00514 g cm(-2), while that of the undoped glass was 0.00710 g cm(-2).