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Viscosity and Softening Behavior of Alkali Zinc Sulfophosphate Glasses
Author(s) -
Da Ning,
Krolikowski Sebastian,
Nielsen Karsten H.,
Kaschta Jochen,
Wondraczek Lothar
Publication year - 2010
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.03707.x
Subject(s) - fragility , softening , viscosity , glass transition , softening point , alkali metal , relaxation (psychology) , thermodynamics , materials science , zinc , mineralogy , chemistry , composite material , metallurgy , polymer , organic chemistry , psychology , social psychology , physics
We report on the softening properties and viscosity of glasses from the system ZnO–Na 2 O–SO 3 –P 2 O 5 for low‐temperature sealing applications. Up to a ratio of network‐forming ions PO 4 3− :SO 4 2− of about 2:1, a gradual substitution of P 2 O 5 by SO 3 results in decreasing glass transition and softening temperatures. At the same time, decreasing kinetic fragility is observed, noteworthy even for decreasing the total amount of network former from 44 at.% to 39 at.%. Thermomechanical and calorimetric analyses reveal a distinct SO 4 2− ‐promoted relaxation phenomenon at temperatures significantly below the macroscopic glass transition temperature, which is interpreted as a result of the formation of an increasingly interconnected assembly of SO 4 2− and PO 4 3− units with increasing SO 3 content.