Effect of seawater constituents on the performance of thermal spray aluminium (TSA) in marine environments
Rosa Grinon Echaniz
Shiladitya Paul
Rob Thornton
2381/43637
https://figshare.le.ac.uk/articles/journal_contribution/Effect_of_seawater_constituents_on_the_performance_of_thermal_spray_aluminium_TSA_in_marine_environments/10208945
Thermally sprayed coatings are often used to mitigate corrosion of offshore structures. They
act as a physical barrier to the aggressive marine environment and as a sacrificial distributed
anode for low carbon steel. In such environments, the severity of material degradation depends
on many factors. The effect of temperature, exposure time or the presence of microorganisms
are the focus of many studies for example, however the effect of the different ions present in
seawater remains largely unexplored. The chemical composition of the water changes
considerably depending on the location; industrial, glacial, estuarine, etc. In addition, when
Thermal Spray Aluminium (TSA) protects steel in seawater, calcareous matter precipitates as
a result of the cathodic polarisation and subsequent localized increase in pH. Therefore,
understanding how ions such as magnesium (II), calcium (II) or carbonates alter the coating
properties in marine environment is important. This paper reports the experimental work carried
out with TSA coated steel samples with defects in order to simulate mechanical damage or
erosion of the coating. The combination of electrochemical tests and surface characterization
provided evidence of the efficiency of the calcareous bilayer that forms on top of steel reducing
the TSA degradation.
2019-03-27 10:12:54
thermal spray aluminium
cathodic protection
calcareous deposits
accelerated corrosion