Fabrication and properties of novel low-melting glasses in the ternary system ZnO–Sb2O3–P2O5

Glasses in the ternary system ZnO–Sb2O3–P2O5 were investigated as potential alternatives to lead based glasses for low temperature applications. The glass-forming region of ZnO–Sb2O3–P2O5 system has been determined. Structure and properties of the glasses with the composition (60 − x)ZnO–xSb2O3–40P2O5 were characterized by infrared spectra (IR), differential thermal analysis (DTA) and X-ray diffraction (XRD). The results of IR indicated the role of Sb3+ as participant in glass network structure, which was supported by the monotonic and remarkable increase of density (ρ) and molar volume (VM) with increasing Sb2O3 content. Glass transition temperature (Tg) and thermal stability decreased, and coefficient of thermal expansion (α) increased with the substitution of Sb2O3 for ZnO in the range of 0–50 mol%. XRD pattern of the heat treated glass containing 30 mol% Sb2O3 indicated that the structure of antimony–phosphate becomes dominant. The improved water durability of these glasses is consistent with the replacement of easily hydrated phosphate chains by corrosion resistant P–O–Sb bonds. The glasses containing ⩾30 mol% Sb2O3 possess lower Tg (<400 °C) and better water durability, which could be alternatives to lead based glasses for practical applications with further composition improvement.