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Sulphuric acid (H2SO4) is widely used in various industrial processes, including fertilizer production. However, its highly corrosive nature poses a significant challenge to the materials used for transport and storage, particularly metals and alloys. This review provides an overview of corrosion types in iron and nickel-based alloys, commonly employed for handling sulphuric acid. The paper discusses alloy selection based on their corrosion behavior in different H2SO4 concentrations, temperatures, and harsh conditions such as erosion-corrosion and presence of contaminants. Additionally, it highlights the use of inhibitors and polymeric coatings for corrosion protection. Finally, the paper outlines future research directions for corrosion protection of alloys in sulphuric acid environments.

Wear (erosion/abrasion) and corrosion act in synergy in several industrial installations where corrosive fluids circulate together with a solid phase causing mutual damage. High entropy alloys (HEAs) are promising materials to be used in that type of environments because of their outstanding chemical, electrochemical and mechanical properties. While several review articles are currently available on corrosion, mechanical properties, development of HEAs, microstructure, and HEA coatings, there is an undeniable lack of a comprehensive and critical review focusing on the tribological behaviour and tribocorrosion of bulk HEAs. This work aims to collect, summarise, and critically review the major accomplishments and progresses of HEAs over the last 20 years dealing with wear, corrosion, and wear-corrosion resistance. It highlights the most significant aspects that can influence the performance of HEAs including the change of the base alloying elements, the influence of the temperature, heat treatment, and wear test parameters (load, velocity, duration, distance). Furthermore, operating mechanisms, together with the relationship between microstructure and wear resistance, and between microstructure and corrosion resistance will be described. Finally, the articles that have been reported in the literature dealing with tribocorrosion of HEAs will be reviewed. The results of this study are expected to guide potential researchers and provide them with the sum of current trends in HEAs in terms of corrosion resistance, wear resistance and the synergy of both, in the hope of helping them to make the right decision to design and develop new HEAs or improve the research on the existing ones.