Assessing corrosion resistance of 2D nanomaterial-based coatings on stainless steel substrates

Two dimensional (2D) materials have elicited considerable interest in the
past decade due to a diverse array of novel properties ranging from high
surface to mass ratios, a wide range of band gaps (insulating boron
nitride to semiconducting transition metal dichalcogenides), high
mechanical strength and chemical stability. Given the superior
chemo-thermo-mechanical properties, 2D materials may provide
transformative solution to a familiar yet persistent problem of
significant socio-economic burden: the corrosion of stainless steel (SS).
With this broader perspective, we investigate corrosion resistance
properties of stainless steel coated with 2D nanomaterials; molybdenum
disulfide (MoS2), boron nitride (BN), bulk graphite in 3.5 wt. % aqueous
NaCl solution. The nanosheets were prepared by a novel liquid phase
exfoliation technique and the coatings were made by a paint brush to
achieve uniformity.  Open circuit potential (OCP) and
potentiodynamic plots indicate the best corrosion resistance is provided
by the MoS2 and the BN coatings. Superior performance of the coating is
attributed low electronic conductivity, large flake size, and uniform
coverage of SS substrate, which likely impeded the corrosive ions from the
solution to diffuse through the coating.