Study on microstructure, mechanical properties and corrosion resistance of NbCN-Cu composite films

In this research, NbCN-Cu films with different Cu contents were prepared by multi-target confocal RF magnetron sputtering. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray Photoelectron Spectroscopy (XPS), Raman spectrometry, Energy Disperse Spectroscopy (EDS), nano-indentation, and electrochemical workstation were used to characterize and analyze the microstructure, mechanical properties and corrosion resistance of the films. The results show that the NbCN-Cu composite films consist of crystalline face-centered cubic(fcc) Cu, face-centered cubic(fcc) NbCN, hexagonal close-packed(hcp) NbCN, and amorphous graphite and CNx phases. When Cu content was 2.6 at.%, a coherent interface was detected between fcc-Cu and fcc-NbCN, hcp-NbCN, and dislocations were detected at the coherent interface when Cu content increased to 9.5 at.%. With the increase of Cu content, the microhardness of the film first increased and then decreased. NbCN-Cu composite film with Cu content of 2.6 at.% had the highest hardness of 32.8 GPa and remarkable corrosion resistance. The self-corrosion potential of the film was 0.18 V and self-corrosion current density was 2.29 × 10−6 A/cm2.