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Polyamide 66 (PA66) nanocomposites were prepared by compounding carbon nanotubes (CNTs) using an elastic high‐shear kneading method, and the mechanism to understand their excellent properties was verified. In addition, we developed a microwave heat treatment that increases toughness quickly and at low cost. By combining 6.6 vol% or more of CNTs, PA66 with improved mechanical properties, such as higher elastic modulus and yield strength, was achieved, making it possible to obtain a composite having excellent high‐temperature characteristics that does not melt even at a temperature above the melting point. These effects appeared to be due to defibration of CNT aggregates and isolation and dispersion in PA66. A lamellar crystal of PA66 grows around the CNT, forming an interphase. The higher performance appeared to be attributable to a continuous three‐dimensional structure in which CNTs are bound via the interphase, and the improvement of the elastic modulus of the composite material was tentatively ascribed to a Halpin‐Tsai model in which the size of the unit cell of the three‐dimensional structure is introduced. The resulting CNT/PA66 composite materials are superior not only in performance but also in price. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanofiber–copper composite films with different types of nanofibers were fabricated by an electrodeposition process. Four types of carbon nanofibers, vapor-grown carbon nanofibers without heat treatment, vapor-grown carbon nanofibers with heat treatment, vapor-grown carbon nanofibers with smaller diameters, and vapor-grown carbon nanofibers with a cup-stacked nanostructure were used. The carbon nanofibers were homogeneously dispersed in sulfate copper plating baths in the presence of polyacrylic acid. Electrodeposition was carried out under galvanostatic conditions using these copper plating baths. The deposition resulted in electrodeposited copper films containing the carbon nanofibers distributed homogeneously. The surface morphology of the carbon nanofiber–copper composite films was observed to be affected by the type of carbon nanofiber used. [Copyright &y& Elsevier]

Nickel-coated carbon nanofibers have been prepared by an electroless deposition process. The carbon nanofibers were pre-treated prior to the nickel electroless deposition. Polyacrylic acid was used to disperse carbon nanofibers in the pre-treatment solutions. The carbon nanofibers were coated homogeneously with nickel by the electroless deposition process using an electroplating bath containing sodium hypophosphite as a reducing agent. The process resulted in a powdery-nickel-coated carbon nanofiber material. [Copyright &y& Elsevier]

Carbon nanofiber–copper composite powder is prepared by an electrodeposition process using a copper plating bath containing homogeneously dispersed carbon nanofibers. Particles of the composite with a spiky ball structure are accumulated on the plating electrode during the initial stage of electroplating, and can be separated easily to give a powder carbon nanofiber–copper composite. The particle size can be controlled by selecting appropriate electroplating conditions. [Copyright &y& Elsevier]

Abstract: Nickel–carbon nanofiber composites were synthesized by means of pulse-reverse (PR) electrodeposition technique from a standard Watts nickel plating bath using a cationic polymer as the dispersing agent of nanofibers. The obtained composites were characterized by electron probe X-ray microanalyzer, field-emission scanning electron microscope and X-ray diffractometer to demonstrate their microstructures. Results clearly showed that the composites were formed as the continuous films filled by a large amount of individual Ni-coated nanofibers with a closely packed arrangement. The PR electrodeposition enhanced the carbon nanofiber concentration compared to the DC electrodeposition in the nickel–carbon nanofiber composites. The morphological features and the composition of composites exhibited controllable characters by selectively modulating the PR electrodeposition parameters. [Copyright &y& Elsevier]

Abstract: Carbon nanotube (CNT) is an effective reinforcement used to improve the mechanical and thermal responses of metal matrix composites. It is, however, obvious that segregation of CNTs due to their strong van der Waals forces will produce material defects, decreasing the material properties. An advanced powder metallurgy process that disperses un-bundled nanotubes has been developed, and it is applied to fabricate a Mg matrix composite reinforced with CNTs in the present study. When approximately 1vol.% CNTs were added, the extruded pure Mg and AZ31B alloy composites displayed an extremely large increase of the tensile yield stress of 25–40%, compared to Mg materials containing no CNT. HR-TEM verified the presence of MgO thin layers of 2–4nm thickness, originating in the oxide surface films of the raw Mg and its alloy powders. These layers exist at the interface between α-Mg and the un-bundled nanotubes. The oxide layer showed a homogeneous mixture containing both α-Mg and CNT. This mixture resulted in an effective tensile loading transfer at the interface, which significantly improved the tensile strength (TS) and yield stress (YS) of the Mg composites. However, the elongation was less than 5%, and the composites exhibited a very poor ductility. This was because the MgO layers at the interface between α-Mg and CNT were very ductile. [Copyright &y& Elsevier]