Hexagonal Boron Nitride: The Thinnest Insulating Barrier to Microbial Corrosion

Area of Science:

• Materials Science
• Corrosion Science
• Microbiology

Background:

• Microbial corrosion poses a significant threat to metallic infrastructure.
• Sulfate-reducing bacteria (SRB), such as Desulfovibrio alaskensis G20, are primary drivers of microbially influenced corrosion (MIC).
• Existing protective coatings often face limitations in thinness, efficiency, or environmental compatibility.

Purpose of the Study:

• To evaluate the efficacy of a single layer of two-dimensional hexagonal boron nitride (SL-hBN) as an ultra-thin insulating barrier against microbial corrosion.
• To assess the performance of SL-hBN on copper (SL-hBN-Cu) against Desulfovibrio alaskensis G20 under various conditions.

Main Methods:

• Electrochemical techniques, including cyclic voltammetry and linear polarization resistance, were employed.
• Corrosion resistance was tested against both planktonic and sessile (biofilm) forms of Desulfovibrio alaskensis G20.
• The performance of SL-hBN-Cu was compared directly against bare copper (Cu).

Main Results:

• SL-hBN-Cu demonstrated significant suppression of corrosion induced by planktonic SRB, maintaining effectiveness at potentials up to 0.2 V (vs Ag/AgCl).
• The peak anodic current for SL-hBN coatings was approximately 36 times lower than that of bare Cu.
• Linear polarization resistance confirmed SL-hBN's barrier function against SRB biofilm corrosive effects, achieving ~91% corrosion inhibition efficiency.
• SL-hBN proved impermeable to aggressive bacterial metabolites and suppressed galvanic effects due to its insulating properties.

Conclusions:

• A single layer of hexagonal boron nitride functions as an exceptionally thin yet highly effective insulating barrier against microbial corrosion.
• SL-hBN coatings offer superior corrosion resistance compared to bare copper and performance comparable to much thicker commercial coatings.
• The impermeability and insulating nature of SL-hBN make it a promising advanced material for combating microbially influenced corrosion.