Ceramic-glass composite high temperature seals for dense ionic-conducting ceramic membranes

A basic principle for selecting inorganic sealing materials for dense ionic -conducting ceramic membranes is described for high temperature permeation/ reaction experiments. Based on this principle ceramic-glass composite seals consisting of the Pyrex glass and the ceramic powder of the membrane were developed and successfully used to seal a number of different dense ceramic membranes at high temperatures. The ceramic-glass composite seal is typica lly composed of 40-50 wt.% membrane material powder, 20-50 wt.% Pyrex glass and 5-20 wt.% additive such as sodium aluminate and boron oxide. The prope rties of ceramic-glass composite seal can be tailored to obtain suitable we ttability, viscosity, chemical inertness, thermal expansibility, and bondin g strength for good sealing results. A success rate for sealing these ceram ic membranes of nearly 100% is possible using the ceramic-glass composite r ecipe if the correct sealing procedure, including seal paste preparation, i s carefully followed. (C) 2001 Elsevier Science B.V. All rights reserved.