Fabrication of low temperature foaming glass materials using hydrothermal treatment

Abstract

In order to prepare functional porous glasses, the fabrication of low temperature foaming glass materials was achieved using a hydrothermal treatment. The hydrothermal hot pressing technique was applied to 63mass%SiO 2-27mass%Na2O-10mass%B2O3 glass at 523 K. The water releasing behavior of the glass was analyzed by TG-DTA. A macroscopic change was observed after the heat treatment at 423-673 K and foaming was exhibited at temperatures as low as 473 K. The mechanism for foaming of the hydrothermally treated glass is discussed from the microstructure change observed with laser microscopy. Furthermore, the application of hydrothermally treated glass is proposed and demonstrated. © 2008 ISIJ.