Results of paint coating full-scale tests for coastal and ship structures in the tropical climate of Vietnam

Full-scale tests are widely used to reliably evaluation the service life of paint and varnish coatings by assessing changes of their protective and decorative properties. Four-year exposure program was carried out in the tropical marine climate in South Vietnam (Dam Bay climate station of the Tre island, Nha Trang) of alkyd, chlorinated rubber coatings on low carbon steel, as well as epoxy coatings of various thicknesses with zinc-rich primer, urethane and acrylic outer layers. The tests were conducted on the base of the existing standards in the field of paints and varnishes intended for coastal and ship structures and were accompanied by the data collection and analysis of the meteorological factors for the classification of the area according to the degree of corrosiveness of the atmosphere. The change in the decorative properties of paint coating was assessed by visual and instrumental methods. The protective efficiency of the coatings was assessed by the time of occurrence of the first local defects or complete destruction of coating layers. According to the results of the conducted field tests, it was found that paint coating combinations correspond to expected lifetime in tropical climate from 2 to 5 years. A typical group suitable for a given climate is a two-component epoxy paint with an acrylic topcoat. A zinc-containing primer is recommended as an anticorrosive undercoat.

1. Laptev, A. B., Kolpachkov, E. D., Kurs, M. G., Lebedev, M. P., & Lutsenko, A. N. (2018). Development of a method for determining the service life of structures made of polymer composite material. Plastic mass, (9-10), 36- 40. doi: 10.35164/0554-2901-2018-9-10-36-40.

2. Gladkikh, A. V., Course, I. S., & Course, M. G. (2018). Analysis of the data of full-scale climatic tests, combined with the application of operational factors, non-metallic materials (review). Proceedings of VIAM: electron. scientific and technical zhurn, 10(70), 74-82. doi: 10.18577/2307-6046-2018-0-10-74-82.

3. Polyakova, A. V., Krivushina, A. A., Goryashnik, Yu. S., & Bukharev, G. M. (2016). Tests for microbiological resistance in natural conditions of different climatic zones. Proceedings of VIAM: electron. scientific and technical zhurn., 4(40), 97-105. Available at: http://www.viam-works.ru (accessed 18.05.2016). doi: 10.18577/2307-6046-2016-0-4-11-11.

4. Varchenko, E. A., Course, M. G. (2019). Influence of the parameters of the corrosive environment on the properties of structural metallic materials during tests in sea water (review). Proceedings of VIAM: electron. scientific and technical zhurn., 5(77), 85-93. doi: 10.18577/2307-6046-2019-0-5-85-93.

5. Corrosion of metals and alloys. Corrosivity of atmospheres. Classification, determination and estimation. (2017). ISO 9223: 2017.

6. Corrosion of metals and alloys – Corrosivity of atmospheres – Guiding values for the corrosivity categories. (2012). ISO 9224: 2012.

7. Preparation of steel surfaces prior to application of paints and varnishes and related products. Visual assessment of surface cleanliness. Part 1. Oxidation state and preparation grades of uncoated steel surface and steel surface after complete removal of previous coatings. (2014). GOST R ISO 8501- 1-2014.

8. Paints and varnishes – Corrosion protection of steel structures by protective paint systems – Part 5: Protective paint systems. (2019). ISO 12944-5:2019.

9. Unified system of protection against corrosion and aging. Paint coatings. Appearance assessment method. (2012). GOST R 9.414-2012.

10. Paints and varnishes – Evaluation of degradation of coatings – Designation of quantity and size of defects, and of intensity of uniform changes in appearance. (2016). ISO 4628:2016.

11. General requirements for the competence of testing and calibration laboratories. (2017). ISO/IEC 17025:2017.

12. Course, M. G., Karimov, S. A. (2014). Full-scale accelerated testing: method features and methods for assessing the corrosion characteristics of aluminum alloys. Aviation materials and technologies, (1), 51-57. doi: 10.18577/2071-9140-2014-0-1-51-57.

13. Anufriev, N. G., Smirnova, N. E., & Ivanov, A. M. (2003). Application of modern zinc-filled primers in painting works. Industrial painting, (2), 11-13.

14. Unified system of protection against corrosion and aging (ESZKS). Climatic test stations. General requirements. (1983). GOST 9-906-83.

15. Paints and varnishes. Method for determining the gloss of non-metallic paint coatings at 20 °, 60 ° and 85 °. (2006). GOST R 52663-2006 (ISO 2813: 1994).

16. Paints and varnishes. Colorimetry. Part 2. Measurement of color.(2006). GOST R 52662-2006 (ISO 7724-2: 1984).

17. Paints and varnishes. Colorimetry. Part 3. Calculation of color differences. (2005). GOST R 52490-2005 (ISO 7724-3:1984).

18. Paints and varnishes. Colorimetry. Part 1. Basic provisions. (2005). GOST R 52489- 2005 (ISO 7724-1:1984).

19. Coil coated metals – Test methods – part 14: chalking (Helmen method). (2014). EN 13523-14:2014.

20. Mikhalov, A. A., Tidblad, J., & Kucera, V. (2004). The classification system of ISO 9223 standard and the dose-response functions assessing the corrosivity of outdoor atmospheres. Protection of Metals, 40(6), 541-550.

21. Startsev, V. O., Slavin, A. V., & Nikolaev, E. V. (2020). Study of the content of aggressive ions in the atmosphere and seawater of the Gelendzhik Bay. Proceedings of VIAM: electron. scientific and technical zhurn, 10(92). 106-115. doi: 10.18577/2307-6046-2020-0-10-106-115.

22. Wu Dinh Wui. (1994). Atmospheric corrosion of metals in the tropics. Moscow: Science.

23. The official website of the Vietnam Environment Department. Environmental Monitoring Portal. Northern Environmental Monitoring Center. [Electronic resource]. – Available at: http://cem.gov.vn/.

24. Dara, T. O. (2017). Evaluation of Atmospheric Corrosion in Steels for Corrosion Mapping in Asia. Doctor Thesis. Graduate School of Engineering, Yokohama National University, (Sep).

25. Le Thi Hong Lien, Pham Thy San, Hoang Lam Hong.Results of studying atmospheric corrosion in Vietnam 1995-2005.et al (2007). Science and Technology of Advanced. Materials, 8(7-8), 552.

26.