YAG and Y2O3 laser ceramics from nonagglomerated nanopowders

Abstract

Undoped and Nd or Yb doped laser grade yttrium aluminum garnet and (Y,La) 2 O 3 ceramics with a transmittance above 80% in the 1 µm lasing region have been prepared by solid state reactions using nonagglomerated Y 2 O 3 and Al 2 O 3 nanopowders. The Y 2 O 3 nanopowders were prepared via laser evaporation, chemical precipitation from urea solutions, and grinding of commercially available Y 2 O 3 in a purpose designed laboratory scale attritor at stirrer rotation rates of up to 1500 rpm. The YAG ceramics were prepared using commercially available Al 2 O 3 . After grinding, all of the powders had a particle size on the order of a hundred nanometers. Green compacts produced from the nanopowders were sintered in a vacuum furnace between 1615 and 1750°C to give highly transparent ceramic samples.

Effect of nanoparticle concentration on coagulation rate of colloidal suspensions

“…( 34) is limited by the condition of a small particle charge: v AE i Ψ ≪ 25 mV, where v AE i is a valence of ions in the solution. This condition is often not satisfied for real suspensions [38,39,40,41]. However, according to the analysis performed in [32], violation of this condition weakly affects the spatial distribution of the potential, which indicates a rather wide range of applicability of the relations (34).…”

Comparative characteristics of Yb:(YLa)2O3laser ceramics

“…Then, the powder was compacted by cold isostatic pressing into a disk 20 mm in diameter and 4 mm in thickness. Sintering was performed in a vacuum furnace with graphite heaters at a temperature of 1625 °C for 12 h [23].…”

Highly transparent Yb-doped (LaxY1−x)2O3 ceramics prepared through colloidal methods of nanoparticles compaction

“…A characteristic feature of the laser synthesized nanoparticles is a metastable phase structure, which is caused by extremely fast cooling, when the laser plasma intermingles with air [25]. This monoclinic Y 2 O 3 lattice transforms to cubic, when the particles are heated [26]. If the phase transformation concurs with ceramics sintering, it causes fracturing of the ceramics compacted with uniaxial, pulse-magnetic or cold isostatic pressing [27].…”