Improving oxidation resistance of porous FeAl-based intermetallics with high boron/yttrium alloying
(College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China)
Abstract: The coalloying with high contents of chromium (Cr), boron (B) and yttrium (Y) for porous B2-structured FeAl intermetallics fabricated through reactive synthesis was conducted. The oxidation behaviors of porous FeAl-based materials were investigated by evaluating the pore-structure evolution, oxidation kinetics and oxide-scale configuration. The results show that with the coalloying of high contents of Cr, B and Y, the oxidation mass gains of porous FeAl materials at 600-800 °C are significantly reduced. The combination of B enriched on the surface of oxide scales and Y located at the scale-metal interface promotes the formation of thin protective nodular α-Al2O3 oxide scales. It is indicated that introducing relatively high contents of reactive elements such as B and Y can benefit the selective growth of α-Al2O3 scales at relatively low temperatures without pre-treatment.
Key words: FeAl; intermetallics; yttrium; high-temperature filter material; oxidation; porous material