The present work describes the use of low energy ion beam induced defects in controllably producing metallic nanoclusters embedded in insulators. The present process avoids the annealing step normally required to form nanoparticles. Fused... more
The present work describes the use of low energy ion beam induced defects in controllably producing metallic nanoclusters embedded in insulators. The present process avoids the annealing step normally required to form nanoparticles. Fused silica and BK7 glasses were implanted with 30 keV Ar+ ions to a dose of 5 1016 ions/cm2 before introducing Cu in the substrates (we shall refer it as pre-mixing implantation). Defects created by pre-mixing implantation are believed to form nano-size pockets available for nucleating the nanoparticles. Cu was introduced in the substrates by ion beam mixing using 30 keV Ar+ ions. The samples were characterized by UV–VIS absorption spectroscopy to obtain the signature of Cu nanoparticles. The surface plasmon resonance (SPR) peak appears between 590 and 636 nm depending on the process parameters. We have established a process, which gives a fine control over the size of nanoparticles using the premixing implantation dose and beam mixing dose. The size of nanoparticles decreases with an increase in pre-mixing implantation dose and with an increase in beam mixing dose mono-dispersed particles are formed.
Pure uranium dioxide and uranium dioxide-gadolinium oxide (5 and 10%) fuels used in this study were prepared by the solution-gelation (sol-gel) technique. The fuels were then coated with boron carbide by chemical vapor deposition. Boron... more
Pure uranium dioxide and uranium dioxide-gadolinium oxide (5 and 10%) fuels used in this study were prepared by the solution-gelation (sol-gel) technique. The fuels were then coated with boron carbide by chemical vapor deposition. Boron carbide was produced from the reaction of carbon tetrachloride and boron trichloride with excess hydrogen, in a tube furnace at 1000, 1100, and 1175 deg. C. The Fourier transform infrared data of boron carbide deposited on a silica glass were in agreement with the ones in the literature. The experiments showed that the composition of the coating changed with deposition temperature. There was boron-rich coating at low-temperature deposition, and carbon-rich coating at high-temperature deposition. The morphology and the thickness of the coating have been investigated by using scanning electron microscopy and X-ray diffraction spectroscopy.
