Influence of the particle size on the mechanical and electrochemical behaviour of micro- and nano-nickel matrix composite coatings

Abstract

The aim of this work is the production and characterization of composite nickel matrix electrodeposits. Pure nickel and composite nickel matrix deposits containing either micro- or nano-particles of silicon carbide were prepared using a Watts type bath. The electrodeposition was carried out under both direct and pulse current conditions at different frequencies. With the same quantity of powder in the bath, the embedded micro-powder content is about 25-30%w while the nano-powder content is always less than 1%w. The mechanical properties of the nano-composites increases despite the low ceramic content. SEM micrographs of the microstructure and XRD-line profile analysis show that the presence of ceramic powder in both baths changes the crystallisation process leading to enhanced mechanical properties even at ceramic contents less than 1%, as in the nano-composite case. The presence of the ceramic phase and changes in the microstructure both decrease the mass loss during abrasion by up to 70% for micro-composites and 45% for nano-composites

Electrodeposition of Metal Matrix Nanocomposites: Improvement of the Chemical Characterization Techniques

“…In addition the results show that the ultra-fine SiC is more difficult to co-deposit than the coarse SiC, and the rate determined step is controlled by the transferring process of loose adsorption to strong adsorption (Wang & Wei, 2003). With the same quantity of powder in the bath, the embedded micro-powder content is about 25-30 wt % while the nano-powder content is always less than 1 wt % ( Zanella et al, 2009;Shao et al, 2002). The smaller the particle the most important are colloidal forces (van der Waals, electrostatic attraction/repulsion and hydrophobic/hydrophilic interaction forces).…”

“…Nevertheless it must be highlighted that the metal matrix morphological and structural characteristics are strongly affected by the particles presence. Furthermore the co-deposition of a sufficient amount of nonagglomerated particles should lead to production of harder and more resistant coatings (Zanella et al, 2009). Particle-reinforced composite coatings based on nickel and alumina are being applied in different technological fields with high demands on friction and corrosion resistance (Jung et al, 2009).…”

“…However the results are often contradictory and inconsistent and they are, therefore, difficult to compare with micro-composites (Medeliene, 2002;Malfatti et al, 2005;Zanella et al, 2009). The mass transport of the inert particles towards the cathode surface is a crucial factor in determining the extent of their occlusion within the growing metallic matrix (Zhou et al, 1997).…”

Improving the properties of mild steel by ternary multilayer composite coating via electrodeposition route

“…It is noteworthy to see the impact of the deposit on the properties of the coating. Though this is expected reason had been that increase in the hardness value are often attributed to the particle inclusion in the Zn matrix [4,7] which helps in the built-up of adhered thin crystal. Multilayer crystal visible at the interfaces in either heterogeneous or homogeneous nature as a result of agglomeration or stable precipitation cause significant changes in hardness characteristics.…”

“…Isolation of structural activeness of protective coating also gives proactive resistance against environmental corrosiveness. Though, surface coatings must provide a continuous barrier to a substrate, and any imperfection can become the focal point for degradation and corrosion of the substrate if not carefully fabricated [4][5][6]. The quality of a coating depends on many factors besides the nature of the materials involved.…”