# Spark Plasma Sintering and Electrospark Deposition of High Entropy Alloys with Elemental Variation

## TL;DR

This paper introduces a new method to create high-performance high-entropy alloy coatings using spark plasma sintering and electrospark deposition.

## Contribution

A novel combined SPS-ESD processing route for HEA coatings with preserved chemical integrity and phase stability is proposed.

## Key findings

- Phase stability and lower porosity were achieved by increasing SPS temperature by 50 °C.
- Coatings showed uniform elemental distribution and no contamination during processing.
- Microfissures formed after six ESD layers due to reduced ductility and rapid cooling.

## Abstract

A novel processing route of producing CrFeNiMo, Co0.5CrFeNiMo, and Al0.5CrFeNiMo high-entropy alloy coatings was proposed in this work. Pre-alloyed HEAs were consolidated by spark plasma sintering (SPS) in order to fabricate electrodes for electrospark deposition (ESD) coatings on carbon steel substrates. Investigations were performed to observe aspects such as phase composition and stability, contamination level, homogeneity, elemental distribution, and microstructural integrity. The results indicated phase stability and lower porosity when increasing the SPS temperature by 50 °C for all cases, with tetragonal distortion related to the HEAs’ severe lattice distortion core effect. The coating surface analysis indicated that a continuous and compact coating was obtained, correlated with the ESD layering count, but microfissures were present after 6 layers were applied due to the reduced ductility combined with rapid cooling under Ar atmosphere. The chemical integrity of both the sintered samples and the coatings was preserved during the processing, revealing a uniform elemental distribution with no contaminations or impurities present. The results indicated successful HEA sintering and deposition, highlighting the potential of the combined SPS-ESD process for high-performance material fabrication with possible applications in aggressive environments.