artificial seawater. As shown in Fig. 7 and Table 4, it is observed that
the corrosion current density value (icorr) of the CrN coating is low.
With the increase of C2H2 flow rate, the corrosion current density
value shows a descending trend until 10–15 sccm, which is the
lowest corrosion current density value at about 7.27 107 A/cm2
. It may be attributed to the small grain size, dense structure and defect
of the coatings, which is consistent with the result of TEM, SEM and
roughness. Qin [44] and Aung [45] pointed out that the corrosion