Oxidation of Al-Co Alloys at High Temperatures

Patrik Šulhánek; Marián Drienovský; Ivona Černičková; Libor Ďuriška; Ramūnas Skaudžius; Žaneta Gerhátová; Marián Palcut

doi:10.3390/ma13143152

Oxidation of Al-Co Alloys at High Temperatures

Materials (Basel). 2020 Jul 15;13(14):3152. doi: 10.3390/ma13143152.

Authors

Patrik Šulhánek¹, Marián Drienovský¹, Ivona Černičková¹, Libor Ďuriška¹, Ramūnas Skaudžius², Žaneta Gerhátová¹, Marián Palcut¹

Affiliations

¹ Faculty of Materials Science and Technology in Trnava, Slovak University of Technology in Bratislava, J. Bottu 24, 91724 Trnava, Slovakia.
² Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko g. 24, 01513 Vilnius, Lithuania.

Abstract

In this work, the high temperature oxidation behavior of Al₇₁Co₂₉ and Al₇₆Co₂₄ alloys (concentration in at.%) is presented. The alloys were prepared by controlled arc-melting of Co and Al granules in high purity argon. The as-solidified alloys were found to consist of several different phases, including structurally complex m-Al₁₃Co₄ and Z-Al₃Co phases. The high temperature oxidation behavior of the alloys was studied by simultaneous thermal analysis in flowing synthetic air at 773-1173 K. A protective Al₂O₃ scale was formed on the sample surface. A parabolic rate law was observed. The rate constants of the alloys have been found between 1.63 × 10^-14 and 8.83 × 10^-12 g cm^-4 s^-1. The experimental activation energies of oxidation are 90 and 123 kJ mol^-1 for the Al₇₁Co₂₉ and Al₇₆Co₂₄ alloys, respectively. The oxidation mechanism of the Al-Co alloys is discussed and implications towards practical applications of these alloys at high temperatures are provided.

Keywords: Al alloy; Co alloy; complex intermetallic; oxidation kinetics; oxide scale.

Abstract

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