Real-time dissolution of a compositionally complex alloy using inline ICP and correlation with XPS

Yao Qiu,Nick Birbilis,Thomas Gengenbach,Oumaïma Gharbi,Hamish L. Fraser,Ruiliang Liu,Sebastian Thomas,Sanjay Choudhary

doi:10.1038/s41529-020-0112-3

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.

Highlights

The recent interest in high entropy alloys (HEAs)[1,2,3] has generated a large number of studies regarding alloys that are derived from the design concepts behind high entropy alloys
Of the works reported to date that have focused on the corrosion of HEAs, compositionally complex alloy (CCA) and multi-principal element alloys (MPEAs), there is, in the general case significant evidence that such alloys are highly corrosion resistant[3,8,9,10,11,12]
It is noted that at all times, the itot signal remains lower than the ipstat signal, which is indicative that not all of the polarising signal is converted to ion dissolution; meaning that a surface film is developing during the anodic polarisation scan

Summary

Introduction

The recent interest in high entropy alloys (HEAs)[1,2,3] has generated a large number of studies regarding alloys that are derived from the design concepts behind high entropy alloys. It is noted that at all times, the itot signal remains lower than the ipstat signal, which is indicative that not all of the polarising signal is converted to ion dissolution; meaning that a surface film is developing during the anodic polarisation scan.

Results

Conclusion