No abstract

No abstract

A Rapidly Solidified Powder (RSP) metallurgical FeCrAl alloy, Kanthal APMT, was exposed in dry and humid O 2 for 72 h at 900-1,100°C. The formed oxide scales were characterized using gravimetry in combination with advanced analysis techniques (SEM, EDX, TEM, XRD, AES and SIMS). The oxide scales were at all exposures composed of two-layered a-Al 2 O 3 scales exhibiting a top layer of equiaxed grains and a bottom layer containing elongated grains. A Cr-rich zone, originating in the native oxide present before exposure, separated these two layers. The top a-Al 2 O 3 layer is suggested to have formed by transformation of outwardly grown metastable alumina, while the inward-grown bottom a-Al 2 O 3 layer had incorporated small Zr-, Hf-and Ti-rich oxide particles present in the alloy matrix. The scale also contained larger Y-rich oxide particles. Furthermore, in the temperature range studied, the presence of water vapour accelerated alloy oxidation somewhat and affected scale morphology.

No abstract