Improvement in comprehensive properties of nanocomposite coatings electro-codeposited with nitride and ceria

Abstract

Metal matrix composite coatings have attracted scientific and engineering interest because of their excellent mechanical properties. Nano-Si3N4 reinforced nickel coatings with different ceria contents were fabricated by electrodeposition. The microstructures, hardness, and tribological properties as well as corrosion behaviors of the composite coatings were studied in detailed. The results show that incorporation of ceria nanoparticles into the nickel matrix can decrease the grain size and facilitate the (111) texture of the coatings, leading to a smooth surface, compact microstructure, and dispersion-strengthening composites. The 6CeO2 coating with the highest hardness of 520 HV50g demonstrates the best wear resistance, while the 3CeO2 coating shows the best corrosion resistance with the smallest i corr value of 0.0972 μA/cm2. The study suggests a significant improvement in mechanical and anti-corrosion properties by incorporation with the ceria nanoparticles, which has important implications for the surface protection of engineering materials.

Enhanced mechanical properties and corrosion resistance of electro-deposited NiCoP composite coatings with ZrB2 particle addition

“…The NiCoP-6 g/l ZrB 2 sample coating has the largest R ct of 360 kΩcm 2 , implying the best anti- corrosion property, which is consistent with the Tafel investigation. In addition, increasing the ZrB 2 loading to 12 g l −1 in the bath would lead to deterioration of corrosion resistance owing to the aggregation of ceramic particles and inhomogeneous surface microstructure, which is consistent with previous study [30,55].…”

“…However, NiCoP-ZrB 2 composite coatings show a different surface appearance that is composed of spherical and cauliflower-like nodules with a radius of 5∼30 microns, which could be attributed to the effect of hindering the normal growth of NiCoP crystalline grains by incorporating ZrB 2 particles [30]. Figure 3(d), which is the enlarged image for figure 3(c), clearly shows some tiny particles with a size of submicron.…”

“…With the increasing demand for protective coatings used in harsh working conditions, the co-deposition of second-phase particles into the nickel-based coatings provides a viable route to enhance the corrosion and tribological properties of the composite coatings [28][29][30]. These second-phase particles can be hard particles, such as Si 3 N 4 [31], Al 2 O 3 [32], TiO 2 [33], CeO 2 [34], SiO 2 [35] and SiC [36,37], which would enhance the wear resistance of nickel-based coatings.…”