Breaking the continuity of the Al2O3 oxide scale by additions of Cr in Co-Al-W-based superalloys

• DOI: 10.1016/j.corsci.2021.109594
• Publication Date: 2021-05-28T15:12:37Z
• Authors: Zhida Liang; Florian Pyczak; Andreas Stark; Ziyuan Rao; Steffen Neumeier; Mathias Göken
• Keywords: info:eu-repo/classification/ddc/670; 670; 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences

The paper presents the effect of small amounts of Cr alloying on the oxidation behavior of a Co-9Al-9W-2Si alloy. A small amount of Cr alloying inhibits the formation of a continuous Al$_2$O$_3$ scale in the oxide layers. The exact mechanism is explained by studying the transient oxidation stages. Cr addition can increase the diffusion rate of oxygen in the oxidation scale. Al is consumed very fast by forming Co(Al,Cr)$_2$O$_4$. This impedes the formation of Al$_2$O$_3$. As a result, the few formed Al$_2$O$_3$ particles do not merge to a continuous scale in the oxide layer.<br/>Published by Elsevier Science, Amsterdam [u.a.]<br/>Corrosion science 189, 109594 (2021). doi:10.1016/j.corsci.2021.109594<br/>