Transformation-assisted consolidation of Y2O3:Eu3+ nanospheres as a concept to optical nanograined ceramics

Sinterability of nanopowders of terbia solid solutions with scandia, yttria, and lutetia

“…This process can provide the system with an additional driving force leading to densification. It is known that a lattice transformation can activate the process of dislocation diffusion, resulting in the effective densification of ceramics [16]. After the reduction of TbO x , the linear shrinkage of the sample continues up to a temperature of 1370 ℃, after which the shrinkage rate begins to decrease.…”

Low-temperature fabrication of Al 2 O 3 -ZrO 2 (Y 2 O 3 ) nanocomposites through hot pressing of amorphous powders

“…As reported by Yavetskiy [20], the cubic to monoclinic transformation of Y 2 O 3 speeded up the mobility of diffused atoms and the rotation of nanograins, and promoted the densification in hot pressing. In this work, the transition of amorphous phase into crystalline solids was likely to benefit the atomic mobility and enhance the mass diffusion, and the particle rearrangement was speeded up as a result.…”

“…What is more, the transformation from amorphous to crystalline phase took place easily, with large decrease in free energy, which highly promoted the densification in hot pressing. As widely reported in literatures [17][18][19][20], the densification of powders could be assisted by transition from metastable to stable phase. According to Bowen [18], phase transition from gamma to alpha alumina played an important role in preparation of nanograined dense ceramics by improving the particle rearrangement and coalescence.…”

“…Furthermore, the phase transition during sintering can speed up the diffusion atomic mobility and particle rearrangement, which are beneficial to the efficient consolidation of dense structure [17][18][19]. This method has been employed to various ceramic systems, for the purpose of taking advantage of transformation from metastable to stable phase, such as anatase to rutile transition of TiO 2 [17], gamma to alpha transition of Al 2 O 3 [18,19], and cubic to monoclinic transformation of Y 2 O 3 [20]. However, sintering or hot pressing promoted by crystallization, i.e., transition from amorphous to crystalline phase, was seldom reported.…”

Comparison of luminescent properties of Y2O3:Eu3+ and LaPO4:Ce3+, Tb3+ phosphors prepared by various synthetic methods

“…UV excitation of Ce 3+ occurs through a 4f 1 →4f 0 5d 1 transition and then energy transfer from Ce 3+ to Tb 3+ arises, resulting in a Tb 3+ emission from the 5 D 4 → 7 F J (J = 0-6) relaxation. Y 2 O 3 :Eu 3+ and LaPO 4 :Ce 3+ , Tb 3+ have been synthesized through various methods such as spray pyrolysis [10,11], microemulsion [12,13], combustion [14,15], sol gel [16,17], hydrothermal [18,19], homogeneous precipitation [20,21], and co-precipitation [22,23]. The microstructure and physical properties are largely dependent on the characteristics of the precursors in the controlled synthesis and thermal decomposition conditions.…”