Authors: Konstantin A. Agapov | Van Tuan Tran | Valery Trusov | Denis I. Kuznetsov | Anzhela A. Gribankova
Source: Труды Санкт-Петербургского государственного морского технического университета (article, 2025-12-16)
Field: Materials Science — Materials Chemistry

Biocidal zinc coatings: development and performance for marine structure protection BACKGROUND: The paper presents the results of research into new protective coatings for marine structures in tropical climates. The studies were conducted within the framework of the scientific research project «Ecolan T-1.1, Task 9», implemented with the support of Joint Vietnam-Russia Tropical Science and Technology Research Center. This work is integrated into the center’s comprehensive scientific agenda and aims to address pressing challenges in the field of material protection under tropical conditions. The main focus was on studying the impact of the marine environment on galvanized steel and the effectiveness of coatings modified with biocidal additives. A protective system based on electrochemical galvanizing with a biocidal component has been developed. Marine testing conducted in the waters of the East Sea (Khanh Hoa, Viet Nam) demonstrated an 80% reduction in biofouling and high corrosion resistance of the coatings. The obtained results demonstrate the promising potential of applying the developed compositions for protecting ship structures. The findings provide a scientific basis for further development and implementation of environmentally friendly protective coatings in marine engineering and tropical construction applications. The study investigates the development of environmentally friendly anti-corrosion coatings for offshore structures. There’s a need to replace toxic biocidal compounds with safe alternatives due to the high biofouling rate in the coastal zone of tropical seas. AIM: To study the performance of zinc coatings with organic additive compounds to protect steel structures from biofouling and corrosion in the marine environment. METHODS: The study used: St3 steel samples measuring 175×250×3 mm; sulfate electrolyte for galvanizing with zinc sulfate concentration of 200–300 g/l; zinc coatings with addition of organic compounds (OC 1–4). The methodology of marine testing in the East Sea (Khanh Hoa, Viet Nam); microscopic analysis; iodometric titration; gravimetric method for determining the corrosion rate. RESULTS: The research has shown a significant reduction in biofouling and corrosion on samples with biocidal additives. Control samples were characterized by intensive formation of marine organism colonies, while samples with additives maintained surface integrity. The corrosion rate decreased by 50%, with maximum protection (61%) achieved using OS 4 (1 mmol/L, 1 A/dm²). The growth of sulfate-reducing bacteria was suppressed: the latent period was 48 hours, and the life cycle of Desulfovibrio was 7 days. The concentration of biogenic hydrogen sulfide decreased significantly. Zinc coatings with additives formed a dense structure with reduced permeability. The developed coatings represent a promising environmentally friendly alternative to traditional antifouling compounds while maintaining the functionality of structures in a marine environment. The economic efficiency was confirmed by the use of St3 steel. CONCLUSION: The developed coatings with organic additives provide effective protection of steel structures from biofouling and corrosion in the marine environment. The findings may be used to develop new anti-corrosion materials for marine equipment and structures and ensure their long-term operation under intensive biofouling conditions. The issue of ship structure protection from biofouling in tropical waters is of particular importance due to the high colonization intensity of underwater surfaces by marine organisms in the coastal zone of Viet Nam. Existing protective systems do not show the required performance in corrosive marine environments, necessitating the development of new high-performance composite solutions. Galvanization ; Biofouling ; Environmentally friendly ; Corrosion ; Seawater ; Zinc Corrosion Behavior and Inhibition ; Marine Biology and Environmental Chemistry ; Material Properties and Applications