In-situ growth of carbon nanotubes from Ni-based coatings and their wear properties

Direct growth of carbon nanotubes (CNTs) from Ni-based coatings on copper substrate was conducted by a hydrothermal approach. Detailed structural characterization revealed that, Ni–P and Ni nanoparticles of 30–200 nm diameters were bridged or wrapped by bundles of CNTs throughout the whole spaces of coatings. During sliding wear tests, the volume loss of copper substrate is 4.6 times of CNTs in-situ reinforced Ni-based coatings at the wear time of 60 min. Catalyzed by {111}, {220} or {311} plane of polyhedral Ni nanoparticles of Ni-based coatings, direct nucleation and growth of straight CNTs were performed under hydrothermal conditions, which exhibited good load transferring ability and low friction coefficient during wear tests, led to the improvement of wear properties.

► Catalyzed by Ni nanoparticles of coatings, straight carbon nanotubes were directly grown.
► Ni-P and Ni Nanoparticles were bridged or wrapped by carbon nanotubes.
► Improvement of wear properties was achieved.