Preparation and Properties of MoO_3-V_2O5-P_2O5-Fe_2O_3 Glasses

Glasses in the MoO3-V2O5-P2O5-Fe2O3 quaternary system were prepared as potential replacements to lead-based frits for low temperature sealing applications. The glass forming regions were explored and the glass forming ability, thermal expansion, and water durability were investigated. Results show that MoO3-V2O5-P2O5 ternary system has strong glass forming ability, which extended down to 10mol% P2O5. The glass forming region in the MoO3-V2O5-P2O5-Fe2O3 quaternary system becomes relatively wider while the stabilities of the glasses against crystallization are still strong with 10mol% Fe2O3. With the increasing content of Fe2O3 the glass forming region becomes smaller. The glass forming ability in this quaternary system is most strong as the ratio of MoO3/V2O5 equals to 1.5. The thermal expansion coefficient can be increased and the water durability improved by adding Fe2O3 content into the MoO3-V2O5-P2O5 ternary system. Trivalence iron ions can enter into phosphate chain and form Fe-O-P.bond in place of P=O double bond, hereby increase the water durability of glasses. Many glass compositions in the system of MoO3-V2O5-P2O5-Fe2O3 have a thermal expansion coefficient of 60-110×10-7/℃ and a dissolution rate in deionized water at 90℃ of 8.0×10-9g·cm-2·min-1, which will be a good alternative to lead-based sealing frits.