Oxidation mechanism of the Inconel 601 alloy at high temperatures

✍ Scribed by H. Buscail; S. Perrier; C. Josse

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: German
• Weight: 829 KB
• Volume: 62
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.200905519

✦ Synopsis

The Inconel 601 alloy oxidation was performed in air, in the temperature range 1000-1150 8C, during 90 h. Kinetic results show that the parabolic behavior is always followed in this temperature range. The Arrhenius plot of the k p values shows two different activation energies. Between 1000 and 1050 8C the activation energy is E a1 ¼ 160 AE 10 kJ/mol. In the 1050-1150 8C temperature range a higher value is calculated E a2 ¼ 252 AE 20 kJ/mol. The E a2 value and the X-ray diffraction (XRD) results and scanning electron microscope (SEM) energy dispersive X-ray spectroscopy (EDS) examinations are in accordance with a scale growth mechanism limited by a growing Cr 2 O 3 scale acting as a diffusion barrier. In the 1000-1050 8C temperature range the activation energy is lower and the structural analyses show that the oxide scale is not only composed of Cr 2 O 3 . Then, the oxide scale is composed of titanium oxides (TiO 2 and Ti 2 Cr 7 O 17 ) and chromia mixed together. A doping effect of the chromia scale by titanium can be envisaged. Our results also show the presence of some Mn 1.5 Cr 1.5 O 4 at the external interface. This external subscale spalls off easily during cooling after the highest temperature oxidation tests. Nevertheless, XRD results and SEM-EDS observations show that the Cr 2 O 3 scale remains very adherent on the substrate and can give a good oxidation protection. This good adherence can be related to the presence of a low amount of aluminum in the Inconel 601 alloy composition.