Mechanical Properties of Electrodeposited Ni-SiO₂ Nanocomposite

Abstract

Nanocomposite materials consisting of a nanocrystalline Ni matrix with grain size ranging from 23 to 40 nm, and nano-size SiO2 particles with average particle size of 7 nm, have been produced by pulse electrodeposition. Grain size was controlled by peak current density. It was observed that SiO2 particles precipitated within grain interior by the transmission electron microscopy (TEM). Hardness and tensile strength of nanocomposites with a grain size larger than 35 nm was higher than that of nanocrystalline pure Ni possibly as a consequence of Orowan precipitation hardening. However, hardness of Ni-SiO2 nanocomposites with a grain size smaller than 30 nm was the same as that of nanocrystalline pure Ni. It was considered that the SiO2 particles do not contribute to hardening because deformation occurs by a grain-boundary-mediated mechanism such as grain-boundary sliding.

Nanocrystalline nickel dispersed with nano-size WO3 particles synthesized by electrodeposition

“…10. The Hall-Petch relations in pure electrodeposited nanocrystalline Ni reported by the present authors [21] and El-Sherik [31] are also shown for comparison. According to our data, the hardness of pure nanocrystalline Ni and Ni-WO 3 with an average grain size of 45 nm is approximately 450 and 550 HV, respectively.…”

“…Another method of synthesizing bulk nanocrystalline metals is electrodeposition, which is, from a synthesis point of view, one of the oldest methods used to produce nanostructured materials [16,17]. Nanocrystalline metals dispersed with hard particles have generally been plated using an electrolyte with suspended hard particles such as SiC [18], Al 2 O 3 [19], TiO 2 [20], and SiO 2 [21]. Similarly, particle size has been limited to dimensions larger than several microns to avoid agglomeration of particles during synthesizing.…”

Advances in precision micro/nano-electroforming: a state-of-the-art review

“…Nano SiO 2 has unique physical and chemical characteristics due to its small size, large specific surface area, rich active hydroxy group, diversified hydroxyl structure, high reactivity, and strong adsorption power. Miyamoto et al [210] studied the mechanical properties of electrodeposited Ni-SiO 2 nanocomposite. They observed that it was at a grain size of 35 or 40 nm that the hardness of the Ni-SiO 2 nanocomposite was higher than that of nanocrystalline Ni.…”

Electrodeposited Nanocrystalline Nickel Dispersed with Nano-Size WO₃ Particles

“…With regard to the deformation mechanism of bulk nanocrystalline metals which have been discussed extensively, additional strengthening by fine dispersions in nanocrystalline metals are of increasing interest. 13) For example, additive strengthening by Orowan-type dislocationparticle interaction and the HallPetch effect in nanocrystalline materials has been discussed. 1) In addition to their strengthening, such very fine particles can stabilize the nanocrystalline structure whose low thermal stability is a drawback of nanocrystalline materials and has limited their industrial application in spite of very high interest in the scientific community.…”