© 2020, ASM International. In this study, the wear–corrosion synergy of DIN 16MnCr5 steel on samples treated by carburization coating, carburized with manganese phosphate coating, and untreated material were evaluated to select the coating with better mechanical and chemical properties for navy military applications. Initially, thermochemical treatments were carried out to obtain thickness coatings of ~ 50 and ~ 70 microns, respectively. The tribocorrosion test for treated and untreated samples was performed in a 5% NaCl solution, and then open circuit potential and wear loss were calculated using a ball-on-flat configuration according to the ASTM G119-09 standard procedure. The sliding wear test, in the presence or absence of corrosion, was performed with a normal force of 20 N, a distance of 100 m and a sliding speed of 10 mm/s; a counterpart of alumina (ball 4.8 mm of diameter) was used for this purpose. The results showed that the coating carburized with manganese phosphate increased ~ 3.8 times the synergistic effect than that of the untreated material, with the presence of a wear–corrosion regime and degradation mechanism in contrast to a wear-dominated regime for the untreated material.