Strengthening Mechanisms in Multiwalled Carbon Nanotubes Reinforced Co–W Pulse Electrodeposited Coatings

Abstract

Cobalt–tungsten coatings reinforced with multiwalled carbon nanotubes (MWCNTs) were prepared by pulse electrodeposition (PED) from citrate bath dispersed with MWCNTs. Effect of MWCNTs and electrodeposition technique, i.e., PED on the microstructure and properties of these coatings was evaluated. The results show that the incorporations of MWCNTs, substantially improve the hardness of the deposited coatings. PED produces Co–W/MWCNT coatings that are featured by small grain size, low surface roughness, and uniform distribution of MWCNTs in matrix, and consequently display higher hardness. Grain refinement, thermal mismatch, Orowan looping, and shear lag mechanisms have played substantial role in strengthening of the Co–W coatings reinforced with MWCNTs. Investigations suggest that shear lag mechanism has a pronounced role in strengthening these coatings.

Keywords:

• Composites
• Defects
• Deposition
• Mechanism
• Microscopy
• Microstructure