Mechanical and electrochemical properties of NbMoSiC gradient films deposited by adjusting sputtering power of carbon target

NbMoSiC gradient films were successfully deposited on 316L stainless steel by adjusting sputtering power of carbon target, and their microstructure, mechanical and electrochemical properties were comprehensively investigated through SEM, XRD, XPS, Raman, nanoindenter and electrochemical workstation. The results show that the NbMoSiC gradient films exhibit a carbon composition gradient across the thickness direction, which impedes the continuous columnar growth and results in a compact and flawless microstructure. The films also possess multiphase structures of Nb2C, MoSi2, silicon and amorphous carbon, leading to a significant improve-ment in hardness value and elastoplasticity. Furthermore, the electrochemical experiments demonstrated a substantial reduction in the corrosion current density for the NbMoSiC gradient films (3.008 x 10-8 A/cm2) compared to bare 316L substrate (3.687 x 10-7 A/cm2) in artificial seawater medium. The charge transfer resistance of the gradient films (3.482 x 106 omega cm2) has increased by an order of magnitude, indicating an enhanced inhibition effect on the ion transport during the corrosion reaction. The improved corrosion resistance of 316L stainless steel is mainly attributed to strong passivation ability and the dense microstructure formed by the carbon composition gradient structure.

Automated summary

NbMoSiC gradient films were successfully deposited on 316L stainless steel by adjusting sputtering power of carbon target. The films exhibited a carbon composition gradient and multiphase structures, resulting in improved hardness and corrosion resistance. The enhanced inhibition effect on ion transport during corrosion reaction was also observed. The dense microstructure formed by the carbon composition gradient structure contributed to the improved corrosion resistance of 316L stainless steel.