Boron Carbide Nanowires

11 April 2010


One of the hottest areas of materials science is the development of composite materials, that combine the useful features of two or more pure materials. It is often useful to mix the materials as thoroughly as possible but this can be difficult as you get smaller, because the particles often stick together rather than mixing.

Xinyong Tao and collegues have come up with an interesting solution, the humble cotton Nanowire ArrayT-shirt. Cotton is particularly well suited to this purpose because each cotton fibre is covered with tiny hairs, these give it a huge surface area, which gives cotton its remarkable ability to absorb water. These hairs are beautifully distributed and don't aggregate, so if you can convert them into the material you want to distribute they are ideal.

They first carbonised the t-shirt, then surrounded it in boron and heated it up. The carbon then reacts with the boron to form boron carbide nanowires. Boron carbide is the third hardest material known, and is often used in body armour, with other useful properties, such as absorbing neutrons, and temperature resistance. These wires can then be mixed in with a polymer and they showed make it significantly stronger.

The final material they have made is not especially strong, but it is a very interesting way of producing this sort of material, and adding other nanowires such as silicon carbide, or titanium carbide, in a relatively cheap manner.


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