Current Nanoscience - Volume 10, Issue 1, 2014

TaNx(1, 3 & 5 nm) films deposited on the Ag(10 nm)/Si(3 nm)/glass show dense microstructure, and this structure was stable even after annealing at 300 °C in Ar (80%) + O2 (20%) ambient for 5 min. The RMS (Root Mean Square) roughness of the films decreased with increasing the TaNx film thickness. The partial oxidation of TaNx was observed in TaNx(3 & 5 nm)/Ag(10 nm)/Si(3 nm)/glass at 300 °C annealing temperature, but no Ag diffusion happened at this temperature. It indicates that no outward diffusion of Ag occurred during the annealing. The as deposited and annealed TaNx(1, 3 & 5 nm)/Ag(10 nm)/Si(3 nm)/glass films showed better transmittance than Ag(10 nm)/glass films in the visible region. The optical data obtained here was in good agreement with simulated predictions.

The microstructures and electrochemical properties of rapidly-solidified silicon alloys mixed with various forms of carbon have been investigated. Rapidly-solidified Si70Ni15Ti15 (at%) alloy (SNT1515) ribbons were prepared by arc-melting, followed by melt spinning process in vacuum. The obtained ribbons were fragmented by ball milling to produce a fine powder of -500mesh. The alloy powder was mixed with various types of carbon: multi-walled carbon nanotubes, hard carbon, soft carbon, and graphite. Each was added by 2wt% by ball milling for 2 hours. The microstructure of the melt-spun ribbon showed a fine silicon primary phase surrounded by Si7Ni4Ti4 and TiSi2 intermetallic compounds. The additions of carbon to the SNT1515 alloy remarkably improved its cyclic performance. Soft carbon was identified to be the most effective in improving the cycle capacity because of its fine particles and uniform distribution.

Ultrasonic spray pyrolysis (USP) and thermal reaction were combined to fabricate lithium iron borate compound nanopowder in cost-effective and high throughput manner. This procedure exploits USP process to prepare homogenous precursor nanopowders, thereby imparting improved reaction during post thermal process. It is believed to be a distinguished route to produce a cathode material in lithium secondary battery.