A high-resolution characterisation of localised corrosion of AA5083-H111 in simulated seawater by TEM

Abstract

The localised corrosion of aluminium alloy (AA) 5083-H111 in 3.5 wt-% NaCl solution was studied by combing scanning electron microscope (SEM), focused ion beam (FIB) and transmission electron microscopy (TEM) techniques. It was found that the Ti-rich intermetallic particles (IMPs) served as the cathodes and triggered the dissolution of its adjacent Al matrix; as a result, a trench was formed between the IMP and its surrounding Al matrix. Raised 'circles' were identified on the alloy surface at the periphery of the IMPs, which was considered to be the cathodic region on which corrosion products deposited. A sub-surface that consisted of fine Al grains and corroded Al-Mg phases were observed under the raised 'circle' region.

Pitting corrosion of 2A12 aluminum alloy long-scale specimen in simulated seawater splash zone, dynamic waterline zone and full immersion zone

“…Offshore Al alloy equipment has been subjected to seawater and salt spray erosion for a long time, as well as the impact of sea wind and sea waves. The working conditions are complex and harsh, with many corrosion types and high rate, multiple hidden corrosion sites, large corrosion damage degree and so on (Ji et al , 2022). Corrosion of Al alloy not only causes huge maintenance cost, but also has become a key factor to determine the life of marine equipment and ensure the technical and tactical level.…”

Corrosion Susceptibility of Passive Films on 1060, 2024, and 5083 Aluminum Alloys: Experimental Study and First-Principles Calculations

“…5 Al-Mg (5xxx) alloys are mainly used in the marine industry due to their good corrosion resistance. [6][7][8] For all types of Al alloys, a protective passive film forms spontaneously on their surface in ambient atmosphere. 9 However, the passive film becomes unstable and degrades locally, causing localized corrosion in chloride containing environments.…”