In this communication, we show the feasibility of the pulsed laser ablation technique to make very thin, uniform luminescent coatings on particulate systems. To deposit continuous particulate coatings, the laser-induced plume from the target comes in contact with an agitated bed of core particles ~size 1 mm!. The pressure and nature of the background gas ~inert or active! controls the cluster s...

Yttria-stabilized zirconia YSZ is modeled using a cluster expansion statistical thermodynamics method built upon a density-functional theory database. The reliability of cluster expansions in predicting atomic ordering is explored by comparing with the extensive experimental database. The cluster expansion of YSZ is utilized in lattice Monte Carlo simulations to compute the ordering of dopant a...

We calculate the vibrational density-of-states in an insulating nanoparticle that is in weak mechanical contact with a semi-infinite substrate. The work is motivated by a recent experiment by Yang et al., where the low-energy phonon density-of-states of Y2O3 nanoparticles doped with Eu 3þ was measured. Preliminary results presented here, based on the conventional quasiparticle-pole approximatio...

Yttrium silicate coating[5, 6] is a promising candidate for oxidation resistant coating for its low oxygen diffusion coefficient and similar thermal expansion coefficient with silicon carbide. Webster et. al.[7] had prepared yttrium silicate coating on C/SiC using Y2O3/SiO2 slips by slip casting and sintering. The selected sintering parameters were 3 h at 1600 °C in flowing argon. The coating c...

Multiphase (MP) monoclinic and cubic Y2O3 nanoparticles, 40 nm in diameter, were densified by spark plasma sintering for 5–15 min and100 MPa at 1000 C, 1100 C, and 1500 C. Densification started with pressure increase at room temperature. Densification stagnated during heating compared to the high shrinkage rate in cubic single-phase reference nanopowder. The limited densification of the MP nano...

In this paper, we show the feasibility of the pulsed-laser ablation technique to grow 20–30-nm-thick, discrete and continuous coatings on particulate material systems so that the properties of the core particles can be suitably modified. Experiments were conducted with a pulsed excimer laser (l 4 248 nm, pulse duration 4 25 ns) to deposit nanoparticle coatings on Al2O3 and SiO2 core particles b...

The microscopic mechanism leading to stabilization of cubic and tetragonal forms of zirconia (ZrO2) is analyzed by means of a self-consistent tight-binding model. Using this model, energies and structures of zirconia containing different vacancy concentrations are calculated, equivalent in concentration to the charge compensating vacancies associated with dissolved yttria (Y2O3) in the tetragon...