The aluminum atoms in these particles are highly reactive, which means they can bind with a variety of molecules. The resulting bonds can change the physical, chemical and optical properties of the material, including its strength, hardness, ductility and color. These properties make nanoparticle aluminum an ideal candidate for a wide range of applications, from photonics to high-energy composites.
Precise control over the size, shape and polarization of the aluminum particles allows for tuning the spectral absorption of the alloy to provide broad absorbance from the ultraviolet into the visible and near-infrared. In addition, the self-limiting oxide shell around each particle provides long-term stability and enables surface modifications for specific applications.
For example, by coating the surface of aluminum nanoparticles with chlorotrimethylsilane and dimethoxydimethylsilane, researchers can manipulate the oxidation rate of the particles and achieve higher energy release when the materials are subjected to high temperatures and pressures. “This is a new mechanism for converting heat and pressure into useful energy,” said Shubhra Gangopadhyay, a professor of materials science at Mizzou Engineering and principal investigator for the research.
The mechanical performance of the aluminum is also enhanced by the presence of the TiC nanoparticles. In a compression test, the AMNC specimen has significantly fewer slip bands than the pure aluminum specimen, indicating that it can withstand higher compressive loads and has a much higher yield strength. In addition, the TiC nanoparticles help refine the grain structure of the Al matrix. This is evidenced by the very low elastic modulus of the AMNC specimen, which is nearly double that of the pure aluminum specimen.