Eurasian Journal of Chemical, Medicinal and Petroleum Research

Abstract Dissimilar metal welded joints (DMWJs) are essential components in offshore oil and gas infrastructure, yet they face critical degradation through corrosion-fatigue interaction under sour service conditions. This comprehensive review examines the multi-physics mechanisms governing crack initiation and propagation in DMWJs exposed to sour environments containing H₂S, where fatigue lives can be reduced by factors of 10× to 50× compared to air . The electrochemical and mechanical coupling arises from hydrogen embrittlement, where hydrogen generated at the crack tip diffuses into the fracture process zone (FPZ) and degrades material cohesion . Microstructural heterogeneity across the weld—including the heat-affected zone (HAZ), fusion boundary, and buttering layers—creates complex local stress-strain fields and galvanic corrosion cells that accelerate damage . Welding residual strain and ductility dip cracking have been identified as critical promoters of corrosion fatigue crack initiation in DMWJs, with cracks initiating preferentially at weld interfaces or regions of high residual strain . Advanced predictive models based on hydrogen transport kinetics to the FPZ have been developed to quantify corrosion fatigue crack growth (CFCG) rates over wide ranges of mechanical variables (ΔK, stress ratio, frequency) and environmental variables (H₂S partial pressure, pH, temperature) . The transition from short-crack to long-crack behavior in sour environments reveals that shallow flaws can grow up to an order of magnitude faster than deep flaws at equivalent ΔK, highlighting the non-conservatism of deep-crack data for shallow flaw assessment . This review concludes that effective life prediction requires integrated multi-physics frameworks coupling crack-tip electrochemistry, hydrogen diffusion, and fracture mechanics.

Abstract Electrochemical advanced oxidation processes (EAOPs) have emerged as promising technologies for the degradation of persistent organic pollutants (POPs) through the in-situ generation of reactive oxygen species, particularly hydroxyl radicals (•OH) . However, the practical application of EAOPs faces two critical challenges: the competitive chloride oxidation reaction (COR) caused by chloride ions in real wastewater, which leads to low Faradaic efficiency and severe corrosion of anode active sites, and the limited service life of electrodes due to dissolution of catalytic layers under harsh operating conditions . This comprehensive review systematically examines nanostructured anodes designed for dual-function applications—simultaneously achieving efficient electrochemical degradation of organic pollutants while providing in-situ corrosion protection of metallic substrates. Nanostructuring approaches, including TiO₂ nanotube arrays and hydrophobic surface modification, have demonstrated remarkable performance enhancement: TiO₂-NTs/SnO₂-Sb-PTFE composite electrodes achieve high oxygen evolution potential (2.4 V vs Ag/AgCl), significantly enhanced TOC removal efficiency for phenolic pollutants, and substantial reduction in Sn ion leaching compared to conventional electrodes . Surface hydrophobicity promotes effective release of free hydroxyl radicals from the anode surface into solution, facilitating pollutant mineralization while the hydrophobic PTFE layer acts as a barrier inhibiting anodic dissolution . Anti-corrosion design principles for seawater electrolysis—including selective oxygen evolution reaction active sites, anion exclusion layers, and electronic structure redistribution—offer valuable strategies for enhancing anode stability in chloride-rich environments . Recent advances in iridium-coated titanium anodes demonstrate service lives of 2-5 years with iridium loss below 0.1 mg/cm²/year, while PANI-modified iron anodes achieve corrosion inhibition efficiency of approximately 35% after repeated electrocoagulation treatment cycles . This review concludes that dual-function anodes represent a transformative approach for sustainable wastewater treatment, combining catalytic activity with corrosion resistance.