The evolution of growth morphology and corrosion behavior of electrodeposited Ni-P coatings on alumina borate whisker-reinforced pure aluminum composite

The Ni-P alloy coatings were obtained on alumina borate whisker-reinforced pure aluminum composite by electro-deposition. The initial electro-deposition behavior of the Ni-P alloys on the composite and pure aluminum was studied, respectively. It was found that the composition and the morphology of materials had a distinct effect on the initial electro-deposition behavior of the Ni-P alloys. The Ni-P alloy coatings preferred to nucleate at the composite as compared with the pure aluminum. Moreover, the Ni-P particles were prone to deposit at the whisker/Al interface in the composite. The Ni-P coatings were barely depositing upon the surface of whisker during the plating process. As the deposition time increased, the Ni-P particles that were deposited on the surface of the composite grew gradually. These Ni-P particles linked to each other and eventually covered the whisker surface. Moreover, it can be found that the surfaces of the composite were gradually covered by Ni-P coatings and the anticorrosion performance of the coated composite increased remarkably with the increase in the deposition time. When the deposition time is 60 min, only the Ni-P diffraction peak could be detected. In this case, the coated composite had significantly better corrosion resistant, which is attributed to the surface of composite was perfectly covered by the Ni-P coatings.