Abstract: 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 willbe a good alternative to lead-based sealing frits.

Key words: phosphate glass, glass forming ability, thermal expansion, water durability