Investigating the real-time dissolution of a compositionally complex alloy using inline ICP and correlation with XPS

TL;DR

This study used inline ICP and XPS to analyze the real-time dissolution behavior of a complex alloy, revealing incongruent dissolution patterns and complex surface oxide formation during corrosion.

Contribution

It introduces a combined inline ICP and XPS approach to study real-time corrosion processes in high entropy alloys, providing new insights into their dissolution mechanisms.

Findings

Incongruent dissolution with preferential Al loss

No Ti dissolution until alloy breakdown

Complex surface oxide composition observed

Abstract

The real-time dissolution of the single-phase compositionally complex alloy (CCA), Al1.5TiVCr, was studied using an inline inductively coupled plasma method. Compositionally complex alloys (CCAs), a term encompassing high entropy alloys (HEAs) or multi-principal element alloys (MPEAs), are - in general - noted for their inherently high corrosion resistance. In order to gain an insight into the dissolution of Al1.5TiVCr alloy, atomic emission spectroelectrochemistry was utilised in order to measure the ion dissolution of the alloy during anodic polarisation. It was revealed that incongruent dissolution occurred, with preferential dissolution of Al, and essentially no dissolution of Ti, until the point of alloy breakdown. Results were correlated with X-ray photoelectron spectroscopy, which revealed a complex surface oxide inclusive of unoxidised metal, and metal oxides in disproportion to the bulk alloying element ratio.