Preparation of Ni-W/TiN-Y2O3 composite ceramic coating for metallic parts protection by direct current deposition

摘要

A novel Ni-W/TiN-Y2O3 composite ceramic coating has been synthesized by direct current deposition for metallic parts protection. The structural, morphology, hardness and anti-corrosion properties of the Ni-W/TiN-Y2O3 coating have been evaluated by SEM, EDS, TEM, XRD and EIS methods. Results indicated that the samples have uniform and compact nodular structure without defects. It demonstrated that the TiN and Y2O3 nanoparticles had been uniformly distributed in the composites. The incorporation of TiN and Y2O3 in Ni-W matrix could improve the hardness and anti-corrosion properties. The crystallite size was in the diameter of 13-16 nm. The electrochemical results illustrated that 6-8 Adm(-2) and 30 min were beneficial to the improvement of anti-corrosion behaviors of the produced composite coating. After immersed 168 h in 3.5 wt% NaCl aqueous solution, the coating prepared at 30 min and 2 A dm(-2) owns better anti-corrosion properties. The embedded TiN and Y2O3 nanoparticles in Ni-W matrix could decrease the electrochemical activity and enhance the protective properties.