Electrodeposition of Ni-W/TiN-Y2O3 nanocrystalline coating and investigation of its surface properties and corrosion resistance
The incorporation of TiN and Y 2 O 3 nanoparticles together into Ni-W matrix have been investigated by pulse electrodeposition in present study. The microstructural, surface properties and corrosion resistance of Ni-W/TiN-Y 2 O 3 nanocrystalline coating have been studied. It illustrated that the electrodeposited coatings have dense and nodular structure without defects. Results confirmed that TiN and Y 2 O 3 particles were uniformly embedded in the composites. The embedded particles could improve the hardness and anti-corrosion properties of the obtained coating. The crystallite size calculated based on the preferred orientation (111) plane was of 14–17 nm, illustrating the formation of nanocrystalline structure. The mean R a value was about 84.6 nm. Electrochemical impedance tests revealed that the preferred combination of operating parameters for optimum corrosion resistance was 70%, 1000 Hz, 40 min and 4 A dm −2 . However, the best hardness and anti-wear properties were obtained at parameters of 50%, 500 Hz, 6 Adm −2 and 60 min. The extreme values of hardness and corrosion resistance were not realized simultaneously. The operating parameters should be kept in a certain balance to avoid the formation of inferior properties in any aspects of the coating; then the other performance advantages could be brought into full play. The preferred combination of operating parameters was optimized to be duty cycle of 70%, frequency of 1000 Hz, duration time of 40 min and average current density of 4 Adm −2 , which enabled the electrodeposited coating optimum corrosion resistance and high mechanical properties .
危险品化学品经营许可证（带存储）