Crystallization kinetics of Al2O3-26mol%Y2O3 glass and full crystallized transparent Y3Al5O12-based nanoceramic

Abstract

Transparent Y 3 Al 5 O 12-based polycrystalline ceramics with excessive Al 2 O 3 composition (Al 2 O 3-26 mol%Y 2 O 3 , AY26) have been demonstrated as potential host materials for phosphor applications. However, the crystallization mechanism of AY26 glass has not been thoroughly investigated so far. In this work, the non-isothermal crystallization kinetics of AY26 glass was experimentally analyzed. The AY26 glass depicts high activation energy and crystallization mechanism of volume nucleation followed by three-dimensional crystal growth mode. Based on the analysis, a novel highly transparent YAG-Al 2 O 3 nanoceramic material was elaborated at lower temperature of 963 ℃ by using pressureless glass crystallization. The biphase nanoceramic is characterized by the structure of YAG nanocrystals surrounded with homogeneous thin Al 2 O 3 layers. It is extremely transparent from visible to mid-infrared region, particularly the transmittance can reach the theoretical limit of YAG transparent ceramic in NIR and MIR regions. Besides, it has almost same hardness of 21 GPa with YAG single crystal and YAG transparent ceramic.

Effect of particle size distribution on crystallization behavior of glass‐based seals in reversible solid oxide cells

“…Three equations can be summarized as $${\rm{ln}}( {\frac{\alpha }{{{{( {{T_p} - {T_0}} )}^n}}}} )$$ versus $$1/{T_p}$$ 38 . It is the Kissinger equation when n = 2, T 0 = 0 K; the Augis–Bennett equation when n = 1, T 0 = 300 K; the Ozawa equation when n = 0, T 0 = 0 K.…”

Ce 3+:Lu 3Al 5O 12–Al 2O 3 optical nanoceramic scintillators elaborated via a low-temperature glass crystallization route

“…As reported in Refs. [39,40], these bulk glass precursors were heated at 950-1300 ℃ for 2 h to perform full crystallization, i.e., to produce the transparent ceramics.…”

“…There are two distinct phases, namely the dark phase and bright phase, which fuse with each other to form the whole ceramic materials. The grains of LuAG appear in a bright area due to the higher average atomic number ( LuAG Z ≈ 47.6), and a dark area is composed of the Al 2 O 3 grains with a lower average atomic number ( [39,40]. The in-line transmittance of the as-prepared transparent materials (1.0 mm in thickness) crystallized from the ALu28 glass-based precursors at 950, 1000, 1100, and 1200 ℃ for 2 h were measured in the UV-Vis-NIR and mid-infrared (MIR) regions, as shown in Fig.…”

“…In Refs. [39,40], YAG-based transparent nanoceramic materials with excellent optical and mechanical properties were elaborated at 963 and 1100 ℃ by pressureless full crystallization from the 74 mol% Al 2 O 3 -26 mol% Y 2 O 3 (AY26) bulk glass raised by the containerless solidification process. Thus, the low-temperature glass crystallization technology is a worth-trying synthesis route to avoid the antisite defects in the LuAG-based transparent ceramic materials.…”

Ablation behaviour of coated Al2O3f/Al2O3 composites under oxyacetylene torch flame

“…The coating also maintained the original flat morphology, which showed that the ablation resistance of the ZrO 2 coating was higher than that of the Y 2 O 3 coating. Generally, the coated composites were less affected by ablation than the non-coated [25], although both the Y 2 O 3 and Al 2 O 3 had a very high melting point, it was easy for them to form eutectic compounds with different percentages of Y 2 O 3 . Thus, at around 1900°C, the melting of eutectic compounds could be observed.…”