Thermal Behavior of Alkali Zinc Phosphates

Abstract

Alkali zinc phosphates O 7 ) 5 , which can be prepared both by the solid-phase synthesis and through crystallization from a glass, are studied using high-temperature X-ray powder diffraction. The unit cell parameters as functions of the temperature in the range 20-700°C are analyzed, and the linear anisotropic thermal expansion coefficients are determined. The majority of these compounds are characterized by strong anisotropy of thermal expansion. It is found that the LiKZnP 2 O 7 compound exists in two polymorphic modifications, namely, the low-temperature monoclinic modification and the high-temperature orthorhombic modification.

Formation and structure of ionic (Na, Zn) sulfophosphate glasses

“…Glass formation in the system ZnO-P 2 O 5 -SO 3 -Na 2 O was studied starting from the eutectic pyrophosphate 42Zn 2 P 2 O 7 -58Na 2 ZnP 2 O 7 [33,34] and varying the ratio of SO 3 /P 2 O 5 as well as the content of network modifiers (Table 1). In a first consideration, the focus was set on the ternary of ZnSO 4 -Zn 2 P 2 O 7 -Na 2 ZnP 2 O 7 , but it was found that the glass forming region extends to far beyond the ZnSO 4 -Na 2 ZnP 2 O 7 join (nominally adding an excess of sodium phosphate and/or sodium sulfate).…”