Barkhausen noise emission of naval steel: The impact of seawater corrosion coverage and depth

Abstract

The study examines the corrosion behavior of shipbuilding steel in an artificial marine environment. The steel samples were submerged in artificial saltwater for varying periods, and the corrosion behavior was examined using traditional methods like open circuit potential tests, metallographic observation and surface roughness assessment. The non-destructive magnetic approach using Barkhausen noise was also used. The corrosion process involves the creation of iron oxides and hydroxides, with the rate of corrosion linked to mass reduction. The surface roughness and corrosion depth increase with longer exposure to the corrosive environment. MBN_max drop gradually over time in artificial seawater, while MBN_PP and MBN_FWHM are increased, presenting a linear correlation. The behaviour of magnetic parameters resent a similar trend both in RD and TD. Both MBN_max and MBN_FWHM measurements offer useful insights into the corrosion process and the role of the corrosion layer in the ferromagnetic matrix.