Nicel/carbon nanotubes nanocomposite layers produced by electrochemical reduction method
Maria Trzaska, Marta Gostomska
Quarterly No. 2, 2010 pages 133-137
DOI:
keywords: nanocomposite coatings, nanocrystal nickel coatings, disperse phase, carbon nanotubes
abstract Electrochemical method as a one of the process in surface engineering allowed to obtain materials with high useful properties to applications in industrial branches, materials engineering, nanoscience and nanotechnology. This paper presents some results concerning studies of nanocomposite Ni/CNTs coatings. The coatings have been produced by the electrochemical method in Watts bath on carbon steel substrate (St3S). The used Watts bath has been filled with organic substances and contained disperse phase of carbon nanotubes (CNTs). The bath was enriched with 0.2 g/l of CNTs. The electrodeposition process was performed with constant current density 3 A/dm2 at temperature 45°C. Prior to the process beginning the bath was intensively stirred ultrasonically in order to obtain a homogenous CNTs suspension. During the entire deposition process the bath was stirred mechanically at a speed of 400 rev/min. The performed investigations present the influence of the crystalline size and quantity of CNTs addition as disperse phase on microhardness of produced nanocomposite layers. Structural analysis of produced layers was also performed. On that base the size of crystallites was calculated. The topography and morphology of produced layers are presented. Nanocrystalline structures of nickel coatings were also investigated to have a comparison with composite layers. The structure of CNTs was analyzed by JEOL-1200, JEM-3010 transmission electron microscopes (TEM) and by Raman spectroscopy (Bruker 110S). The morphology and topography of the Ni layers and of the Ni/CNTs composite layers were analyzed by high-resolution scanning electron microscope Hitachi SU-70 and scanning electron microscope Hitachi S-3500N. For the sake of comparison purposes, the structures of the Ni layers and the Ni/CNTs composite layers were also analyzed by Raman spectroscopy. The microhardness of the produced layers was determined with a Vickers hardness indenter, under a load of 20G. It was observed that the layers deposited in the bath with organic additives exhibited much higher hardness with respect to layers produced without ones. The performed investigations of the nanocomposite layers have shown that the addition into the Watts bath of an organic components and disperse phase of CNTs gives possibilities for obtaining nanocomposites with the Ni matrix.