Metal Nanoparticles such as Aluminum nanoparticles, Iron nanopartilces, Zinc nanoparticles and so on have a huge surface area per gram up to several hundred meters, or even higher, and uniform thin interfacial layer and atomic level stepped surface, making it all the particles react instantly when the critical temperature, and the activation point more prone to phase transformation, a large reaction rate per active site. Thus the surface of the metal nanoparticles in the air easily oxidized and loses activity. For the surface protection is of the metal nano powder is very important.

Active protection of metal nanoparticles can start from the design and modification of the surface structure of nanoparticles. The following protection methods are used in general:

1) adsorption of inert gas atoms, or storage of nanomaterials on the bottle or bag filling an inert gas such as nitrogen, argon, etc., sealed;

2) metal element oxide shell an oxide layer apply to surface protection;

3) a plasticizer or binder storage, put the metal nanoparticles into powder with a binder or plasticizer, which is more convenient to use and also to protect the particle surface;

4) organic shell, such as organic thin film forming surfactants could be effective in the absence of air, preventing oxidation of nano metal powder, organic substances and also chemically bonded metal powder coating is also available;

5) nanomaterials and the main ingredient is combined (complex ) into a composite.

Nanocomposite particles is a very promising approach which is a good solution to the active protection of metal nanoparticles, but it still is a challenge to scientists.

by lyla