Temporary Inhibition of the Corrosion of AZ31B Magnesium Alloy by Formation of Bacillus subtilis Biofilm in Artificial Seawater

Abstract

It is well known that microorganisms tend to form biofilms on metal surfaces to accelerate/decelerate corrosion and affect their service life. Bacillus subtilis was used to produce a dense biofilm on an AZ31B magnesium alloy surface. Corrosion behavior of the alloy with the B. subtilis biofilm was evaluated in artificial seawater. The results revealed that the biofilm hampered extracellular electron transfer significantly, which resulted in a decrease of icorr and increase of Rt clearly compared to the control group. Moreover, an ennoblement of Ecorr was detected under the condition of B. subtilis biofilm covering. Significant reduction of the corrosion was observed by using the cyclic polarization method. All of these prove that the existence of the B. subtilis biofilm effectively enhances the anti-corrosion performance of the AZ31B magnesium alloy. This result may enhance the usage of bio-interfaces for temporary corrosion control. In addition, a possible corrosion inhibition mechanism of B. subtilis on AZ31B magnesium alloy was proposed.

Corrosion Behavior of AISI 1045 Steel in Seawater in the Presence of Flavobacterium sp.

“…Similarly, the resistance of the corrosion products film formed on AISI 304 stainless steel increased in the first 10 days of immersion in sterile seawater due to the increase in thickness of the corrosion products (Rodríguez et al, 2006). The corrosion product increased the impedance value of AZ31B magnesium alloy immersed in the artificial seawater (Kang et al, 2019). The increase of the R ct value of the naval carbon steel BV-grade A in natural seawater was due to the increase in the thickness and/or compactness of the corrosion products layer (Belkaid et al, 2011).…”

“…could be attributed to the corrosion inhibition by the biofilm, which were supported by previous studies. Bacillus subtilis increased the impedance value and decreased the corrosion rate due to the formation of the biofilm on the AZ31B magnesium alloy surface (Kang et al, 2019). The P. aeruginosa biofilm increased the R ct values of nickel-zinc alloys, suggesting that this species inhibited corrosion on nickelzinc surfaces (San et al, 2014).…”

Interactions between marine microorganisms and metal: the start point of a new bioinspired solution for corrosion protection

“…In the last decades, new emerging microbial-based technologies have been proposed following the development of more environmental friendly anti-corrosion solutions to increase longevity of structural metals. The fact that microorganisms can influence corrosion behaviors in an advantageous way, the so-called MICI (microbiologically influenced corrosion inhibition) [14][15][16][17] have opened different lines of research, synthesized in [18][19][20]:…”