Fabrication and characterization of reaction bonded silicon carbide/carbon nanotube composites

Abstract

Carbon nanotubes have generated considerable excitement in the scientific and engineering communities because of their exceptional mechanical and physical properties observed at the nanoscale. Carbon nanotubes possess exceptionally high stiffness and strength combined with high electrical and thermal conductivities. These novel material properties have stimulated considerable research in the development of nanotube-reinforced composites (Thostenson et al 2001 Compos. Sci. Technol. 61 1899, Thostenson et al 2005 Compos. Sci. Technol. 65 491). In this research, novel reaction bonded silicon carbide nanocomposites were fabricated using melt infiltration of silicon. A series of multi-walled carbon nanotube-reinforced ceramic matrix composites (NT-CMCs) were fabricated and the structure and properties were characterized. Here we show that carbon nanotubes are present in the as-fabricated NT-CMCs after reaction bonding at temperatures above 1400 °C. Characterization results reveal that a very small volume content of carbon nanotubes, as low as 0.3 volume %, results in a 75% reduction in electrical resistivity of the ceramic composites. A 96% decrease in electrical resistivity was observed for the ceramics with the highest nanotube volume fraction of 2.1%.

Effects of dispersion surfactants on the properties of ceramic–carbon nanotube (CNT) nanocomposites

“…A minimum of 500 readings was taken to measure the grain sizes of each material. The electrical conductivity of the sintered materials was measured using the two-probe method [44] at room temperature. Silver electroded specimens (3 × 3 × 3 mm) were characterized (Equation 1) with a high sensitivity digital micro-ohmmetre (Keithley 580).…”

“…This agglomeration is particularly significant in CVD-grown nanotubes because substantial entanglement of the tubes occurs during nanotube synthesis [44]. For all of the ultrasonication durations, GA+SDS solution disperses CNTs more efficiently as compared to SDS solution and GA solutions alone ( Figure 1).…”

Surface Modification of Natural Fibers Using Bacteria: Depositing Bacterial Cellulose onto Natural Fibers To Create Hierarchical Fiber Reinforced Nanocomposites

“…on the other hand, has been shown to improve adhesion in a wide range of fiber composite systems; of particular relevance is the attachment of carbon nanofibers onto conventional carbon 47,48 or silicon carbide 49 fibers. The improved adhesion will enhance the stress transfer efficiency between the two phases; in turn, an improvement in composite performance was found.…”

Carbon Nanotube-Based Composites for Future Air Force and Aerospace Systems

“…Our recent research has also extended our capability to disperse nanotubes in thermosetting polymer matrices [13,14]. Figure 10 shows TEM micrographs of randomly oriented dispersed nanotube composites in a thermoplastic (polystyrene) and thermoset (EPON 862) polymer matrix.…”

“…After carbonization of the matrix, molten silicon was infiltrated to produce reaction-bonded silicon carbide composites [14]. Figure 13 shows a high-resolution TEM micrograph (JEOL JEM 2010F) where a carbon nanotube is observed protruding from the matrix.…”