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Foam glass obtained through high‐pressure sintering
Author(s) -
Østergaard Martin B.,
Petersen Rasmus R.,
König Jakob,
Bockowski Michal,
Yue Yuanzheng
Publication year - 2018
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/jace.15574
Subject(s) - materials science , sintering , foaming agent , softening point , composite material , porous glass , porosity , glass tube , inert , mixing (physics) , glass transition , inert gas , tube (container) , chemistry , polymer , physics , organic chemistry , quantum mechanics
Foam glasses are usually prepared through a chemical approach, that is, by mixing glass powder with foaming agents, and heating the mixture to a temperature above the softening point (10 6.6 Pa s) of the glass. The foaming agents release gas, enabling expansion of the sintered glass. Here, we use a physical foaming approach to prepare foam glass. First, closed pores filled with inert gases (He, Ar, or N 2 ) are physically introduced into a glass body by sintering cathode ray tube ( CRT ) panel glass powder at high gas pressure (5‐25 MP a) at 640°C and, then cooled to room temperature. The sintered bodies are subjected to a second heat treatment above the glass transition temperature at atmospheric pressure. This heat treatment causes expansion of the pores due to high internal gas pressure. We found that the foaming ability strongly depends on the gas pressure applied during sintering, and on the kinetic diameters of the gases. The pressure for attaining maximum expansion, that is, lowest density and highest porosity, is found to be around 20 MP a.