Abstract:
A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises an aluminosilicate of Group IIA and/or Group IIIB and a Group VB oxide. In one preferred embodiment, the barrier layer comprises 25 to 75 wt.% of the Group VB oxide (Ta, Nb and mixtures thereof) with the balance being barium-strontium aluminosilicate.