Abstract

STELLA, Jorge; SANCHEZ, Analinda  and  RUIZ, Augusto. Morfologías de Oxidación a altas temperaturas de una Superaleación sinterizada ni-Al-Cr . Rev. LatinAm. Metal. Mater. [online]. 2008, vol.28, n.1, pp.18-28. ISSN 0255-6952.

The oxidation in air at 1000, 1050 and 1100ºC of a Ni-based superalloy obtained by powder metallurgy has been studied. Results showed at 1000 and 1050ºC predominant formation of continuous Al₂O₃ outer layers with good protective properties. Mixed oxide layers containing Al₂O₃ and Cr₂O₃ with poor protective properties were observed at 1050ºC. A cellular morphology beneath the layer was identified after 72 h at 1100ºC, which mainly exhibits Al₂O₃ and metallic Ni regions. This oxidation mechanism seems to be related to grain boundary diffusion of the involved species during the oxide growth at low oxygen pressures.

Keywords : Oxidation; Ni₃Al; cellular morphology; powder metallurgy.