Performance of materials in fluidized-bed combustors

Effect of Al content on oxidation behaviour of ternary Fe–Al–C alloys

“…However, the reported literature shows the formation of alumina scale over a range of temperatures, before and after the occurrence of inversion. The authors of these studies have attributed their findings to polymorphic transformation of various form of Al 2 O 3 such as y, g to form a protective a-Al 2 O 3 [27,28]. The inversion in the present case can be related more to the ability of the alloy to preferentially form Al 2 O 3 over either of Fe 2 O 3 and FeAl 2 O 4 than to such a phase transition.…”

Mechanical properties and oxidation behaviour of two-phase iron aluminium alloys with Zr(Fe,Al)2 Laves phase or Zr(Fe,Al)12 τ1 phase

“…The scale adherence of alumina scales formed on ironaluminides during oxidation at temperatures above 900 8C was found to be improved by the addition of small amounts (!0.1at.%) of Zr [12,[30][31][32][33][34]. For an Fe-11.7Al alloy with 0.03at.% Zr, the formation of ZrO 2 was found to improve the adherence of Al 2 O 3 layers and to catalyze the transformation from metastable Q-Al 2 O 3 to stable, protective a-Al 2 O 3 scales on the alloy surface [30].…”

Microstructure Evolution Mechanism in Iron Aluminides/CrMo Steel Composite Prepared by Solid State Bonding

“…The microstructures of iron aluminide are equi-axed with coarse grains of about 300 mm, whereas those of steel exhibit deformed structure. 3 were prepared from the rolled plates and its contact surface for bonding was ground with 1 500 grade SiC paper and 1.0 mm alumina particles. Polished specimens were cleaned by an ultrasonic apparatus in acetone and clamped by alumina jigs.…”

“…Iron-aluminum alloys exhibit high oxidation resistance, which is due to formation of stable and protective a-Al 2 O 3 layer on the surface at higher temperatures than 1 173 K at low oxygen partial pressures such as 10 Ϫ17 Pa. 1) Chemically stable a-Al 2 O 3 (melting point 2 375 K) is formed by polymorphic transformation from various forms of Al 2 O 3 such as q, g at temperatures higher than 1 273 K. [2][3][4][5] The stable layer is formed when the aluminum content in the alloy exceeds 14 at%. 1,6) The authors have proposed a corrosion resistant composite of iron aluminide and steel, expecting an alternative material for corrosion-resistant alloys.…”

“…In a previous study using diffusion couples of iron aluminide with chromium and pure iron, 7) it is reported that the transformation temperature determined by differential thermal analysis (DTA) is well correlated with the microstructure of the iron side in the couple. When the bonding temperature is higher than alpha-gamma transformation temperature (described as A 3 ), columnar microstructure evolved from the joint interface into pure iron, and the composite exhibits high bonding strength. In addition, water quenching from bonding temperatures above A 3 lead to columnar microstructure, and the length of columnar grains increased with bonding time and temperature.…”