Creep in electrodeposited submicrocrystalline nickel and its particle-reinforced nanocomposite

Mechanical Spectroscopy of Annealing Effects in Electrodeposited Nickel/Ceramic Nanocomposites

“…Sample preparation. As described in different details elsewhere [6][7][8][9]12,16], DC electroplating was carried out onto a copper substrate with current densities of 10−60 mA/cm 2 , using a 99.9% pure nickel anode in a 50% aqueous solution of nickel sulfamate containing boric acid and nickel chlo-ride. By co-deposition with 10 g/l of ceramic nanopowder dispersed in the electrolyte, nanocomposites were prepared with 2 vol.% of either SiO 2 or Al 2 O 3 nanoparticles.…”

“…Free-standing films of about 0.05 mm thickness were obtained after mechanical removal of the substrate. Three types of samples with different microstructures [8,12,13,15] were investigated: (1) pure UFG nickel with a grain size about 300 nm, (2) a Ni/SiO 2 nanocomposite with extremely fine (7 nm) SiO 2 particles and a truly nanocrystalline (60 nm) Ni matrix, and (3) a Ni/Al 2 O 3 nanocomposite with a broad, lognormal size distribution of spherical Al 2 O 3 particles (σ = 1.7; median diameter 25 nm) and an average grain size of 150 nm in the Ni matrix. Mechanical spectroscopy was done in a high-vacuum vibrating-reed apparatus [17] equipped with a single, adjustable electrode for both electrostatic excitation and capacitive detection of flexural resonance vibrations (Bordoni-type detection system [18]).…”

“…One way of this extension of electrodeposition to the nanoscale, besides other variants [3−5], has been the co-deposition of Ni with nanopowders such as Al 2 O 3 or SiO 2 [6−9]. The dispersion of the ceramic nanoparticles then causes further hardening and reinforcement not only directly, but also indirectly by reducing the matrix grain size from about 300 nm in pure Ni to about 100 nm or less in the resulting nanocomposites, combined with enhanced stability against grain growth [9,12]. The stabilising influence of the nanoparticles is also seen in creep resistance, microhardness, coercivity, and amplitude-dependent damping [12−14].…”

Challenges and recent developments on nanoparticle-reinforced metal matrix composites

“…The electrostatic repulsion is overcome by the Van der Waals attraction force for an interparticle distance down to 1 nm (Li et al, 2004;Tsai et al, 2010;Sklenicka et al, 2005). The electrostatic repulsion is overcome by the Van der Waals attraction force for an interparticle distance down to 1 nm (Li et al, 2004;Tsai et al, 2010;Sklenicka et al, 2005).…”

Creep behavior of hot extruded Al-Al2O3 nanocomposite powder

“…They explained the differences in the creep activation energies in nanostructured and coarse-grained state by the different contributions of grain boundary sliding to the overall deformation. Sklenička et al [27] studied the creep of submicrocrystalline nickel and its particle-reinforced nanocomposites. They reported higher creep resistance for nano-sized SiO 2 reinforced nickel as compared to the unreinforced metal.…”