Dispersions of multi-wall carbon nanotubes, onion-like carbon, and nanodiamonds in ethylene glycol are produced using a homogenizer and an ultrasonic bath, altering the treatment time. The dispersed particles are then used as reinforcement phase for nickel matrix composites. These nanoparticles are chosen to represent different carbon hybridization states (sp2 vs. sp3) or a different particle geometry (0D vs. 1D). This allows for a systematic investigation of the effect of named differences on the dispersibility in the solvent and in the composite, as well as the mechanical reinforcement effect. A comprehensive suite of complementary analytical methods are employed, including transmission electron microscopy, Raman spectroscopy, dynamic light scattering, sedimentation analysis, zeta-potential measurements, scanning electron microscopy, electron back scatter diffraction, and Vickers microhardness measurements. It can be concluded that the maximum achievable dispersion grade in the solvent is similar, not altering the structural integrity of the particles. However, nanodiamonds show the best dispersion stability, followed by onion-like carbon, and finally multi-walled carbon nanotubes. The distribution and agglomerate sizes of the particles within the composites are in good agreement with the dispersion analysis, which is finally correlated with a maximum grain refinement by a factor of 3 and a maximum mechanical reinforcement effect for nanodiamonds.

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Dispersion analysis of carbon nanotubes, carbon onions, and nanodiamonds for their application as reinforcement phase in nickel metal matrix composites

Tribological behavior of self-lubricating carbon nanoparticle reinforced metal matrix composites

Identical steady tribological performance of graphene-oxide-strengthened polyurethane/epoxy interpenetrating polymer networks derived from graphene nanosheet

Mixed oxide nanotubes in nanomedicine: A dead-end or a bridge to the future?

Tribological properties, thermal conductivity and corrosion resistance of titanium/nanodiamond nanocomposites

Nanodiamond/Ni and Ni coatings were fabricated via brush plating. Nanocrystalline structure of the composite coating was investigated by SEM and XRD. The results showed that the composite coatings are nanocrystalline structure. The hardness of the nanodiamond/Ni composite coating is higher greatly than that of Ni coating. At same time, the reasons of formation nanocrystalline were discussed, which include the nucleation rate with the increase of a high over-potential, the reciprocating motion between brush and work piece, the heterogeneous nucleation of nanodiamond. The nanodiamonds as second phases make grain finer. The nanodiamonds of core-shell structure play the important role in wear resistance and antifriction. So the wear resistance of the composite coatings is significantly higher than nickel coating’s.

The Relationship between Nanocrystalline Structure and Frictional Properties of Nanodiamond/Ni Composite Coatings by Brush Plating

Nanotubular films on the surface of Ti-2Al-15Mn (TC1) alloy were fabricated by electrochemical anodization technique in aqueous ammonium fluoride solutions at 20V for 3h The photoelectrochemical activities of the nanotube arrays were investigated, as well as their phase, structure, composition and photoabsorption properties The photo-absorption in the visible region and the photoelectrochemical response were improved obviously It is attributed to the Mn ion doping of TiO2 lattices Furthermore, the resulted nanotube arrays are expected to have bright application prospects for solar utilization

Fabrication and Photoelectrochemical Properties of Self-Organized Mixed Oxide Nanotubes by Anodization of Ti-2Al-1.5Mn Alloy

The hardness and the wear resistance of the nano-diamond composite coatings were investigated by the micro-hardness tester and the friction tester. The relationship of the nano-diamond concentration, heat treatment temperature and hardness were revealed. These results show that the composite coatings have higher hardness, better wear resistance and lower friction coefficient under the uniform dispersing of the nano-diamond in the nickel matrix. The maximum hardness of the composite coatings reaches HV654 when the nano-diamond concentration is 30%. Frictional coefficient is decreased from 0.185 to 0.16. Moreover, the hardness does not reduce under annealing at 300°C. The frictional mechanism of the composite coatings indicates that the worn nano-diamond could block the direct contact between the composite coating and the standard ring. Spherical nano-diamond particles play the role in the "micro-ball" among the contact surfaces, the frictional coefficient is reduced and the wear resistance is improved.

The Frictional Properties and Mechanism of Nano-Diamond/Ni Composite Coatings by Brush-Plating

Tribology behavior of Nanodiamond(ND) polyurethane(PU)/epoxy(EP) interpenetrating polymer networks hybrid materials were tested by friction wear testing machine. Results showed that when EP content was 30%, resultant PU/EP IPNs exhibited best wear resistance. For ND-PU/EP IPNs hybrids, when the ND addition was 0.2wt%, the best wear resistant ability was obtained. Under dry condition, the effect of wear parameters, such as rotational speed, load and central distance to friction and abrasion value were also investigated.

Tribology Study of Nanodiamond Hybrid Polyurethane/Epoxy Interpenetrating Polymer Networks Materials

Nano-diamond/Ni and Ni coatings were prepared by brush plating. SEM and XRD methods were applied to investigate the morphology, nano-crystalline structure and grain size of the coatings. The results show that the grain size of the brush coatings all is in nanometer scale. The surface morphology of the composite brush coatings is a finer and denser cauliflower-like structure. Meanwhile the reasons of formation nano-crystalline structure are the high over-potential, the discontinuous grain growth resulted from the reciprocating motion and friction between the plating pen and the work piece, the heterogeneous nucleation of the nano-diamond, and the point discharge effect. The nano-diamond as the second phases decreases the grain size of the coating and consequently increase the strength of the composite coatings largely.

Wen Jun Zou

Papers

The Relationship between Nanocrystalline Structure and Frictional Properties of Nanodiamond/Ni Composite Coatings by Brush Plating

Fabrication and Photoelectrochemical Properties of Self-Organized Mixed Oxide Nanotubes by Anodization of Ti-2Al-1.5Mn Alloy

The Frictional Properties and Mechanism of Nano-Diamond/Ni Composite Coatings by Brush-Plating

Tribology Study of Nanodiamond Hybrid Polyurethane/Epoxy Interpenetrating Polymer Networks Materials

Nano-Crystalline Structure and Strengthening Mechanism of Nano-Diamond/Ni Composite Coatings by Brush-Plating