Influence of sintering atmosphere on the microstructure and water durability of SnO–MgO–P2O5 glass

Effects of sintering atmosphere (Ar, air, and O2) on the sinterability and crystallization at 380–470 °C of 60SnO, 10MgO, 30P2O5 (mol%) glass powder, and the water durability of the sintered glass were investigated. Increasing the oxygen partial pressure \( (P_{{{\text{O}}₂ }} ) \) in the sintering atmosphere enhanced the oxidation tendency of Sn2+ to Sn4+ near the surface region of the glass particles. Therefore, the glass viscosity was increased, resulting in the increase in both the temperature of densification and the temperature at which crystalline phases developed. Phase assemblage and the amounts of crystalline phases were also affected by \( P_{{{\text{O}}₂ }} . \) The water durability of the sintered glasses is discussed in terms of the above microstructural parameters.