Fabrication of Metal/Carbon Nanotube Composites by Electro Chemical Deposition

Metal/carbon nanotube (CNT) composites are promising functional materials due to the various superior properties of CNTs in addition to the characteristics of metals, and consequently, many fabrication processes of these composites have been vigorously researched. In this paper, the fabrication process of metal/CNT composites by electrochemical deposition, including electrodeposition and electroless deposition, are comprehensively reviewed. A general introduction for fabrication of metal/CNT composites using the electrochemical deposition is carried out. The fabrication methods can be classified into three types: (1) composite plating by electrodeposition or electroless deposition, (2) metal coating on CNT by electroless deposition, and (3) electrodeposition using CNT templates, such as CNT sheets and CNT yarns. The performances of each type have been compared and explained especially from the view point of preparation methods. In the cases of (1) composite plating and (2) metal coating on CNTs, homogeneous dispersion of CNTs in electrochemical deposition baths is essential for the formation of metal/CNT composites with homogeneous distribution of CNTs, which leads to high performance composites. In the case of (3) electrodeposition using CNT templates, the electrodeposition of metals not only on the surfaces but also interior of the CNT templates is the key process to fabricate high performance metal/CNT composites.

Influence of Double-Pulse Electrodeposition Parameters on the Performance of Nickel/Nanodiamond Composite Coatings

In this study, using 45# carbon steel as the substrate, a first experimental analysis was carried out on the polarisation behaviour of different component wattage plating solutions in order to determine the reasonable content of nanodiamond particles in a nickel/nanodiamond composite plating solution. Secondly, the effect of double-pulse forward and reverse duty cycle and reverse working time on the performance of nickel/nanodiamond composite plating was then investigated by testing the thickness, hardness and surface roughness of the composite plating and observing the surface micromorphology. The experimental results show that, when the content of nanodiamond particles in the plating solution is 5 g/L, the anti-pulse working time, forward and reverse pulse duty cycle of the double-pulse plating parameters are 20, 0.3 and 0.2 ms, respectively, and the composite plating layer prepared by double pulse has good comprehensive performance. This research work provides technical support for the optimisation of process parameters for the preparation of nickel/nanodiamond composite coatings by double-pulse electrodeposition.

Electrodeposition of Ni-W/CNT Composite Plating and Its Potential as Coating for PEMFC Bipolar Plate

In this study, Ni-W/carbon nanotube (CNT) composite platings are electrodeposited onto steel plate as a possible coating material for the polymer electrolyte membrane fuel cell (PEMFC) bipolar plate, which requires high corrosion resistance under acidic environment and low contact resistance. The dispersibility of CNT in the plating bath is improved by surface modification of CNT through hydrothermal treatment in mixed acid solution. The change in electrodeposition behavior of Ni-W plating by CNT addition is investigated by cathodic polarization measurement. The corrosion resistance under acidic environment is evaluated using 0.5M H2SO4 solution and contact resistance of the composite platings is measured and compared with Ni and Ni-W plating. The surface modification of CNT through hydrothermal treatment is found to increase the CNT content in the Ni-W/CNT composite plating up to 0.33 mass.% and sufficient incorporation of hydrothermally treated CNT in Ni-W plating results in low contact resistance and enhanced corrosion resistance than pristine Ni-W plating.

RESEARCHES OF THE POSSIBILITY OF ASSESSING DAMAGE TO THREE-LAYER STRUCTURES BY IMPACT DAMAGE BY METHOD OF COMPUTED X-RAY TOMOGRAPHY

This article describes the results of researches on the assessment of the applicability of the method of computer X-ray tomography for monitoring the internal structure of three-layer structures with carbon composite cladding and aluminum honeycomb, a general description of the method is given. It has been experimentally shown that the method of computed X-ray tomography allows one to evaluate the porosity of carbon composite plating, to identify stratifications resulting from impact. Comparative results of the non-destructive testing of a three-layer carbon composite sample made by autoclave molding from a unidirectional carbon tape and an adhesive epoxy matrix and aluminum honeycomb before and after impact are presented. It was revealed that for the upper lining of a carbon composite, the maximum number of macrodefects of the type stratification occurs directly in the impact zone and adjacent local areas, and leads to a change in the geometry of the skin and honeycomb aggregate, as well as a multiple increase in porosity in comparison with the results of the preimpact test. It should be noted that in the lower skin the porosity due to impact increases slightly, evenly distributed over the volume of the skin, which indicates the occurrence of cracking in the polymer matrix of the carbon composite.Thus, the method of computer x-ray tomography is an effective tool for controlling the damage of three-layer structures by impact.