Role of marine Bacillus subtilis and Pseudomonas aeruginosa in cavitation erosion behaviour of 316L stainless steel

Abstract

This study investigated the effect of marine bacteria (Pseudomonas aeruginosa and Bacillus subtilis) biofilms on the cavitation erosion resistance of 316L stainless steel (316L SS) in artificial seawater (ASW). The 316L SS samples were sorted into three groups and were immersed in ASW, ASW with Pseudomonas aeruginosa (PASW), and ASW with Bacillus subtilis (BASW). After 30 days of immersion, the BASW-immersed sample had fewer corrosion pits than the PASW-immersed samples. Meanwhile, SEM observation suggested that these corrosion pits were susceptible to cavitation erosion. As a result, cavitation erosion resistance of the sample immersed in PASW decreased significantly, while the cavitation erosion resistance of the samples immersed in BASW was not compromised. Moreover, it was found that the increased mass loss during cavitation erosion was positively correlated to the pitting area.