Stability of SrFeO3 based materials in the presence of SiOx species in humid atmosphere at high temperatures and pressures

✍ Scribed by Ingeborg Kaus; Kjell Wiik; Marit Dahle; Morten Brustad; Siv Aasland

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 763 KB
• Volume: 27
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.03.040

✦ Synopsis

Strontium silicate was found on the surface of La 0.2 Sr 0.8 Fe 0.79 Cr 0.2 Mg 0.01 O 3 exposed to hydrogen containing humid atmospheres at 1000 • C and 30 bars. Silica originated from the furnace tube material and was transported via the gas phase as a gaseous silica hydrate. Fe and Sr were initially preferentially expelled from the perovskite grain boundaries to give Sr 2 SiO 4 at the surface, along with a secondary Fe-rich phase and a LaCrO 3 -rich grain boundary region. Eventually, Fe and Sr were drawn from the grains, leaving a porous structure. This investigation highlights the importance of avoiding Si sources near Sr-rich membranes in humid atmospheres at high temperatures.