The effects of D-amino acid enhanced compound bactericide on corrosion resistance behavior and mechanism of 45＃ carbon steel,316L stainless steel and H62 brass in sulfate reducing bacteria(SRB)＋ iron oxidizing bacteria(IOB)were studied by biological culture technology,bactericidal process evaluation,weight loss experiment,electrochemical test and surface analysis. The results showed that the corrosion depth of different metals a year without bactericide was as follows,45＃ carbon steel (0. 104 2 mm / a)＞H62 brass (0. 045 6 mm / a)＞ 316L stainless steel (0. 007 3 mm / a). Because the SRB and IOB in the mixed bacteria have a synergistic effect to accelerate the corrosion of metal materials. After adding the bactericide,the bactericidal rate of SRB and IOB in the mixed bacteria exceeded 99% and 90%,respectively,the polarization curves of the three metals all shifted to the left,the ｉcorr decreased in a varying degree,the corrosion rate reduced significantly,and the depth and number of pitting pits decreased significantly. Moreover,the content of P and S in microbial metabolites decreased significantly,it indicated that the number of viable bacteria decreased sharply. With or without bactericide,316L stainless steel has the best corrosion resistance due to the easy formation of chromium oxide passivation film on the surface,and H62 brass has good corrosion resistance due to Cu2＋ bactericidal effect. The tetrakis hydroxymethyl phosphonium sulphate (THPS)in the compound bactericide can change the properties of cellular enzymes and proteins to cause the death of bacteria,meanwhile D-amino acids can decompose the biofilm on the surface of the metal,which can change the bacteria from the hard-to-kill fixed state to the easy-to-kill floating state to improve the bactericidal effect,and also avoid the formation of high concentrations of extracellular polymer EPS,thereby reduce the corrosion rate of the metal. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.
