B4C nanowire reinforcements Synthesis from carbon template

Nanoscale wires are widely used as structural reinforcement materials in nanocomposites. Among various types of reinforcements, B4C nanowires proved to be promising and have been successfully embedded in different matrixes such as mild steel, Ti, TiB2, BN, Mg and especially Al. Fabrication of these nanostructured materials with controlled scale of production and better properties has been a major challenge in processing of these materials for composites. In this research, boron carbide nanowires were synthesized by high temperature thermal treatment of carbon fibers without using catalyst, where the carbon fibers used as templates. The micro and nano scale carbon fibers were placed in graphite crucible together with B2O3 powders, and were heated for 90 minutes at four different temperatures above 1400 °C in a tube furnace under the protection of Ar gas. This process resulted in B4C nanowires with graphite coating. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were employed to study the effects of treatment temperature on the shape and quantity of the B4C nanowires. In addition to a well-ordered structure, the B4C nanowires synthesized in our process have a uniform structure and contain no catalyst. TEM micrographs also showed the core/shell structure. Results demonstrate that with increasing the treatment temperature, the efficiency of the process increases. In general, nanowires synthesized by our process introduce advantageous characteristics, which can provide better properties for nanocomposites.

کلیدواژه ها:

Boron-Carbide (B4C) ، nanowires ، TEM ، heat treating