**4. Conclusions**

In this study, potentiodynamic polarization curves were employed together with SEM and CLSM techniques to investigate corrosion and microbial corrosion inhibition of BDMDAC for 304SS substrates. The results reveal that BDMDAC achieved satisfactory results against microbial corrosion by *D. desulfuricans* in anaerobic conditions. Addition of 25 ppm BDMDAC could effectively inhibit the growth of *D. desulfuricans*. Surface characterization results revealed no biofilm on the 304SS coupons surfaces after BDMDAC was added to the *D. desulfuricans*-inoculated medium. The electrochemical results revealed deceleration of corrosion caused by the addition of BDMDAC in the *D. desulfuricans*-inoculated medium, which was demonstrated by the decrease of current densities in the anodic region and *Icorr*.

**Author Contributions:** Conceptualization, Y.-L.L.; Methodology, K.-Y.L. and Y.-L.L.; Validation, C.-W.H. and T.-E.C.; Formal Analysis, C.-W.H. and Y.-L.L.; Investigation, C.-W.H. and T.-E.C.; Writing—Original Draft Preparation, C.-W.H. and Y.-L.L.; Writing—Review & Editing, K.-Y.L. and Y.-L.L.; Supervision, Y.-L.L.

**Funding:** This work was funded by the Ministry of Science and Technology, Taiwan, under gran<sup>t</sup> No. MOST 106-2218-E-002-033.

**Conflicts of Interest:** The authors declare no conflicts of interest.
