S. Spanou, E.A. Pavlatou, N. Spyrellis
Proceedings of 7th International Conference “THE Coatings” (2008), October 1-3 2008, Kallithea Chalkidiki, Greece, Ziti Editions (Eds. K.D. Bouzakis, Fr.W. Bach, B. Denkena, M. Geiger), p. 399-408 (oral)
Nanocomposite coatings were obtained by electrochemical codeposition of TiO2 nanoparticles (21 nm) with nickel from an additive-free Watts type bath by applying direct and pulse current conditions. The surface morphology, the crystallographic orientation of nickel matrix, the grain size and the microhardness of the deposits were investigated, along with the distribution and the percentage of the embedded nanoparticles in the nickel matrix, affected by the electrodeposition parameters (pH, current density) and the concentration of TiO2 nanoparticles in the bath. The effect of codeposition percentage of TiO2 nanoparticles and type of imposed current were investigated regarding the microhardness and microstructure of the electrodeposits. Ni/TiO2 composite deposits prepared under either direct or pulse current conditions exhibited a considerable strengthening effect with respect to pure Ni coatings. Moreover, it has been revealed that the microhardness of the composite coatings is associated to the induced crystalline nickel orientation and the nickel grain size.