Enhanced mechanical and wear properties of Ni-W-SiC composite coatings by synergistic influence of micro-nano SiC mixture

Abstract

Ni-W-SiC composite coatings with mixed nano- and micro-sized SiC particles are prepared by the pulsed electrodeposition. The microstructure, microhardness, wear and corrosion resistances of the composite coatings were studied as a function of the mixed ratios of nano- to micro-sized SiC. The results showed that the nano-sized SiC can be carried by micro-sized SiC during the deposition process, resulting in a greater amount of nano-sized SiC being incorporated into the composite coatings without agglomeration. The wear resistance of the composite coatings with a mixture of nano- and micro-sized SiC is improved. The highest microhardness is obtained on Ni-W-SiC coating containing a ratio of nano- to micro-sized SiC particles of 1:3. However, as a result of the blockage of the Faradaic current by the inert SiC particles, composite coatings with the highest total SiC content exhibited the best corrosion resistance. Discussions are conducted in detail regarding the effects of mixture particles on microstructure, microhardness, wear and corrosion resistance of the composite coatings. Moreover, the interaction between the nano- and micro-sized SiC during the deposition process are also discussed.