Nanostructured nickel film deposition on carbon fibers for improving reinforcement-matrix interface in metal matrix composites

The issues in dispersing any form of carbon in metal matrix is the major problem in the field of metal matrix composites with carbon reinforcement (MMCcr). The low wettability of carbon in molten metals and the difference in density are some of the difficulties to obtain a good dispersion of carbon fibers in the matrix and, as a consequence, an improvement of some critical properties for metals in a wide range of application (mechanical properties, electrical properties, optical properties). For this reason, the aim of this work is to obtain a metallic coated carbon fiber to enhance the interaction between the reinforcement and the matrix. Moreover, also the density of carbon fibers could be adjusted depending on the thickness of the coating. Electroless Nickel-Phosphorus Plating (ENP) is one of the candidate to be a coating technique to improve the interaction between the carbon fibers and the metal matrix. Despite of its versatility in terms of complex geometry of the substrate and homogeneity and adhesion of the coating, the presence of the phosphorus in the alloy could create some problems with the metal matrix such as the formation of metal-phosphorus products that can drastically decrease the mechanical properties of the composite. For this reason, in this work, is presented a new way of Electroless Pure Nickel Plating (EPP) without any introduction of phosphorus in the nickel coating. The dependence of the coating thickness and the density of the coated fibers were studied under different plating parameters (temperature of the plating solution, deposition rate and plating solution composition). All the samples were characterized with SEM and XRD and the thickness, density and homogeneity were compared for all the samples obtained

“Nanopartículas de Hierro con Tamaño Controlado Depositadas sobre Clinoptilolita por la Técnica de Electroless Plating Method- Coprecipitación: Síntesis y Caracterización”

En el presente trabajo se ha abordado el estudio de la concentración de HCl sobre la activación con SnCl2 de una Zeolita sintetica tipo A de Sodio, que denominaremos Clinoptilolita (CLT), para la depositación en su superficie de óxidos de hierro de tamaño nanomaetrico mediante una técnica conjunta de Electroless Plating Method-Coprecipitación. La razón de utilizar una zeolita como sustrato surge de querer aprovechar sus dimensiones para obtener depósitos de tamaño nanométrico, esto con el fin de que el sustrato sea evaluado a futuro como un material compuesto que presente propiedades magnéticas, de catálisis heterogénea, conducción térmica o de reforzamiento mecánico, esta ultima si se le llegase a utilizar como carga en polímeros

Competitive Nanotechnologies for Fabrication of Thin Films and Powderlike Nanomaterials

The present paper contains new data on the nanotechnologies for fabrication of fine-grained powderlike particles, films, bulk materials, nanocomposites, nanochips and devices for microelectronics, nanoelectronics, photonics and photocatalysis. The technology providing the replacement of precious metals by nonprecious ones and the exclusion of the use of toxic substances is presented. The developed methods of metallization of various materials have been widely used at the enterprises of the NIS for production of quartz resonators and filters, monolithic piezoquartz filters, photomasks, piezoceramic devices for hydroacoustics and delay lines of colour TV sets (several hundreds million devices were produced), casings of integrated circuits and semiconducting devices, ceramic microplates, precise microwire and film resistors, capacitors, catalysts, etc. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3481

Deposition of Nanofilms by the Electroless Method

In the result of application of the developed technology, Au, Ag and Pd were adequately replaced with nonprecious metal alloys. The nanotechnologies using the electroless deposition are much more advantageous and simpler than other expensive methods of nanotechnology and allow the fabrication of photocatalysts and catalysts by means of deposition of nanocrystals having the specified properties on high-dispersive powder like semiconductors. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3486

Positioning and aligning CNTs by external magnetic field to assist localised epoxy cure

Abstract This work focuses on the generation of conductive networks through the localised alignment of nano fillers, such as multi-walled carbon nanotubes (MWCNTs). The feasibility of alignment and positioning of functionalised MWCNTs by external DC magnetic fields was investigated. The aim of this manipulation is to enhance resin curing through AC induction heating due to hysteresis losses from the nanotubes. Experimental analyses focused on in-depth assessment of the nanotube functionalisation, processing and characterisation of magnetic, rheological and cure kinetics properties of the MWCNT solution. The study has shown that an external magnetic field has great potential for positioning and alignment of CNTs. The study demonstrated potential for creating well-ordered architectures with an unprecedented level of control of network geometry. Magnetic characterisation indicated cobalt-plated nanotubes to be the most suitable candidate for magnetic alignment due to their high magnetic sensitivity. Epoxy/metal-plated CNT nanocomposite systems were validated by thermal analysis as induction heating mediums. The curing process could therefore be optimised by the use of dielectric resins. This study offers a first step towards the proof of concept of this technique as a novel repair technology.</jats:p

Designing hollow nano gold golf balls.

Hollow/porous nanoparticles, including nanocarriers, nanoshells, and mesoporous materials have applications in catalysis, photonics, biosensing, and delivery of theranostic agents. Using a hierarchical template synthesis scheme, we have synthesized a nanocarrier mimicking a golf ball, consisting of (i) solid silica core with a pitted gold surface and (ii) a hollow/porous gold shell without silica. The template consisted of 100 nm polystyrene beads attached to a larger silica core. Selective gold plating of the core followed by removal of the polystyrene beads produced a golf ball-like nanostructure with 100 nm pits. Dissolution of the silica core produced a hollow/porous golf ball-like nanostructure

Ultrasound assisted dispersal of a copper nanopowder for electroless copper activation

This paper describes the ultrasound assisted dispersal of a low wt./vol.% copper nanopowder mixture and determines the optimum conditions for de-agglomeration. A commercially available powder was added to propan-2-ol and dispersed using a magnetic stirrer, a high frequency 850 kHz ultrasonic cell, a standard 40 kHz bath and a 20 kHz ultrasonic probe. The particle size of the powder was characterized using dynamic light scattering (DLS). Z-Average diameters (mean cluster size based on the intensity of scattered light) and intensity, volume and number size distributions were monitored as a function of time and energy input. Low frequency ultrasound was found to be more effective than high frequency ultrasound at de-agglomerating the powder and dispersion with a 20 kHz ultrasonic probe was found to be very effective at breaking apart large agglomerates containing weakly bound clusters of nanoparticles. In general, the breakage of nanoclusters was found to be a factor of ultrasonic intensity, the higher the intensity the greater the de-agglomeration and typically micron sized clusters were reduced to sub 100 nm particles in less than 30 min using optimum conditions. However, there came a point at which the forces generated by ultrasonic cavitation were either insufficient to overcome the cohesive bonds between smaller aggregates or at very high intensities decoupling between the tip and solution occurred. Absorption spectroscopy indicated a copper core structure with a thin oxide shell and the catalytic performance of this dispersion was demonstrated by drop coating onto substrates and subsequent electroless copper metallization. This relatively inexpensive catalytic suspension has the potential to replace precious metal based colloids used in electronics manufacturing