Effect of Pt, Pd, Au and Ag on oxidation behaviour of Fe₃Al intermetallic

Abstract

A study on the effect of the addition of 1 at-% noble elements such as Pt, Pd, Ag and Au on the oxidation resistance of Fe₃Al intermetallic alloy has been carried out at 900, 1000 and 1100°C during 100 h. For comparison, the same tests were performed on a Ni-base alloy type Inconel 600. At all the tested temperatures, parabolic growth rate was observed for the different alloys. The effect of the different noble elements was not unique at the different tested temperature. Thus, at 900°C, addition of Ag increased the mass gain, whereas Pd decreased it; at 1000°C, however, the opposite was true. At 1100°C, the mass gain was decreased by adding Pt, but Pd was very detrimental. In most of the cases, the scales were predominantly formed by Al₂O₃ with minor amounts of Fe₂O₃. Scale spallation was found when the noble elements were randomly distributed on the surface, but when they were finely distributed, the scale did not spall. In all cases, the mass gain for Fe₃Al alloy was lower than Inconel 600 type alloy.

Keywords:

• Intermetallic
• Oxidation
• Noble elements