Title

Oxidation resistance of Mo(Si1-xAlx)2 nanocrystalline films and characterization of their oxide scales by electrochemical impedance spectroscopy

Document Type

Journal Article

Publisher

Royal Society of Chemistry

Faculty

Faculty of Health, Engineering and Science

School

School of Engineering

RAS ID

19306

Comments

This article was originally published as: Xu J., Li Z., Munroe P., Xie Z.-H. (2014). Oxidation resistance of Mo(Si1-xAlx)2 nanocrystalline films and characterization of their oxide scales by electrochemical impedance spectroscopy. RSC Advances, 4(99), 55696-55708. Original article available here

Abstract

To explore the influence of Al alloying on the oxidation resistance of MoSi2, four Mo(Si1-xAlx)2 nanocrystalline films, with differing Al contents, were fabricated on Ti-6A1-4V substrates by a double-cathode glow discharge technique and their cyclic oxidation behavior was characterized at 500 °C in air. The oxidation kinetics of the four Mo(Si1-xAlx)2 films was found to obey a subparabolic behavior with respect to the overall exposure, and their oxidation resistance was improved by Al additions. On the other hand, the electrochemical behavior of the oxide scales developed on the four Mo(Si1-xAlx)2 nanocrystalline films in a 3.5 wt% NaCl solution was studied using electrochemical-impedance spectroscopy (EIS). The impedance data showed that with increasing oxidation time, the oxide scales transformed from a homogeneous and dense structure to a duplex structure consisting of a porous outer layer and a denser inner layer. The resistance of the oxide scales increased with increasing Al addition, implying an enhanced protective ability of the oxide scales by Al alloying in media containing chlorine ions. The findings represent a step forward in improving the surface integrity of alloy components used in the hot zones of jet engines.

DOI

10.1039/c4ra10570b

Share

 
COinS