Modification of passive film on Ti-6Al-4V alloy induced by Bacillus vietnamensis

The utilization of Ti-6Al-4V alloy in marine infrastructures is somehow limited by susceptibility to biofouling and bacteria attachment, making studies on microbes-induced passive film degradation timely matter. The impact of Bacillus vietnamensis on passive film integrity of Ti-6Al-4V alloy was investigated. Electrochemical measurements and surface analysis revealed that, B. vietnamensis , which adhered preferentially on the alpha phase, accelerated dissolution of Ti2O3 in the passive film of Ti-6Al-4V alloy. Power-law model (PLM) revealed the changes in resistivity after exposure to B. vietnamensis. After 21 days of incubation, the icorr value in biotic medium (6.50 +/- 3.4 nA cm-2) was slightly higher than that in sterile medium (1.89 +/- 1.1 nA cm-2), suggesting corrosivity of B. vietnamensis against Ti-6Al-4V alloy. This study established comprehensive understanding of interaction between passive film and marine-corrosive microbial fouling.