| Durable Basalt-Based Chemical-Bonded Coatings Served in Deep Sea Environment Hongpeng Zheng1; 1CORROSION AND PROTECTION DIVISION, NATIONAL LABORATORY FOR MATERIALS SCIENCE,NORTHEASTERN UNIVERSITY, Shenyang, China; PAPER: 207/Coatings/Regular (Oral) SCHEDULED: 17:10/Tue. 29 Nov. 2022/Andaman 2 ABSTRACT: With the rapid developments in deep sea exploration, more and more metallic equipments have been employed in the deep sea environments. As compared with shallow sea and marine atmosphere, the deep sea environments are quite different, showing with relatively low temperature, high hydrostatic pressure, and variable dissolved oxygen contents, etc. However, as the metallic equipment up and down in the ocean, the equipment is subjected to the alternating loads and scours from the sea water, which are the most significant factors that may greatly affect the corrosion behavior of metallic equipment served in the deep sea. The organic coatings are the most widely used and effective method among various anti-corrosion techniques for metals. In particular, epoxy resin based anti-corrosion coatings used in deep sea have been reported previously. In the previous works [1-3], it has been clearly discussed the failure mechanisms for coatings under alternating hydrostatic pressure in deep sea. The alternating hydrostatic pressure (AHP) changed the degradation processes and failure mechanisms, and hence accelerated the failure process. The AHP had great effects on the coating/steel interface and led to a rapid loss of adhesion at initial, then AHP accelerated water diffusion into coatings, and deteriorated the coating physical structure, including enlarging the original pores on coating surface and destroying the pigment/binder interface, both of which weakened the anti-permeability of coating against water. Based upon, our latest research direction is how to improve the problem of weakly bonded interfaces. In this work, epoxy resin based anti-corrosion coatings used in deep sea (two kinds of coating systems were applied, basalt scale coating and the etched basalt scales coating) were studied by in situ electrochemical impedance spectroscopy (EIS), pull-off adhesion test and other coating performance tests, as well as the Fourier Transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM), etc. We investigated the failure mechanisms of epoxy composited coatings under alternating hydrostatic pressure systematically, and the failure models of the pigmented coatings under alternating hydrostatic pressure were proposed. Furthermore, an alternating hydrostatic pressure accelerated test and a prediction model based on the artificial neural network were established to develop the laboratory method of fast evaluation and prediction for organic coatings used in deep sea. The aim of this study is to provide some essential theoretical and experimental guidance for the development of new organic coatings used in deep sea. References: [1] W. Tian, L. Liu, F. Meng, Y. Liu, Y. Li, F. Wang, The failure behaviour of an epoxy glass flake coating/steel system under marine alternating hydrostatic pressure, Corrosion Science, 86 (2014) 81-92. [2] F. Meng, L. Liu, W. Tian, H. Wu, Y. Li, T. Zhang, F. Wang, The influence of the chemically bonded interface between fillers and binder on the failure behaviour of an epoxy coating under marine alternating hydrostatic pressure, Corrosion Science, 101 (2015) 139-154. [3] F. Meng, T. Zhang, L. Liu, Y. Cui, F. Wang, Failure behaviour of an epoxy coating with polyaniline modified graphene oxide under marine alternating hydrostatic pressure, Surface and Coatings Technology, 361 (2019) 188-195. |
