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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.

The wet phosphoric acid (WPA) process equipment is exposed to corrosive and wear conditions with aggressiveness determined by the phosphate rock chemical composition and process parameters employed. Stainless steels and nickel alloys are attractive materials considered for WPA plant construction since they are mechanically and chemically robust to withstand the aggressive environment encountered. This review first describes the WPA process emphasizing on the aggressiveness of the environment to plant construction materials. Then, principles behind design and fabrication of stainless steels and nickel alloys with properties tailored to withstand this aggressive environment are described. To withstand corrosion conditions encountered during the WPA process alloys should contain sufficient chromium (Cr), with some molybdenum (Mo) and nickel (Ni) contents and should possess a homogeneous microstructure. Wear resistance in a specific section of the plant is ensured by adjusting the carbon content and carbide formers contents to obtain adequate carbides for protection from abrasion. Reported data on deterioration rates and failure mechanisms of commonly used alloys is first presented before discussing selection and performance of these alloys in different sections of the WPA plant. Future challenges and opportunities in selection of suitable materials and development of novel materials are finally outlined.

This review highlights the state of art progress in crucible designs which have been identified as showing potential for induction melting three groups of titanium alloys based on the systems; Ti–Al, Ti–Ni, as well as multicomponent Ti-based hydrogen storage alloys. Several important parameters for crucible design, including; crucible-melt interactions, thermodynamic stability, and, thermal shock resistance of different crucibles will be discussed. Based on the findings of the review, the selection criteria for identifying crucibles for melting titanium alloys were outlined and several specific promising solutions were suggested. Keywords: Titanium alloys, Induction melting, Crucible, Chemical stability, Thermal shock resistance