Investigation of YAP/YAG powder sintering behavior using advanced thermal techniques

Abstract

The fabrication process of transparent YAG (Y 3 Al 5 O 12 ) ceramics with an emphasis on examination of the sintering process and microstructural analysis is reported herein. Nanometric powder with an equivalent spherical diameter d BET = 60 nm consists mainly of hexagonal YAP phase (YAlO 3 ). According to sintering analysis carried out using a dilatometer and high-temperature XRD analysis, the phase composition and phase transformation taking place at elevated temperatures accompany the sintering process and the fastest sintering rate was observed at temperatures of YAG formation. Based on the dilatometric and XRD analyses vs temperature, three temperatures were selected for pressureless sintering. Presintered samples were subjected to sintering under isostatic pressure using a hot isostatic pressing, after which transparent YAG was obtained. The best results were obtained for samples presintered at a relatively low temperature of 1600°C, and for thus obtained sample, the in-line transmittance was 64% at k = 808 nm.

A dynamic analysis of the aluminum titanate (Al2TiO5) reaction-sintering from alumina and titania, properties and effect of alumina particle size

“…Simultaneous thermogravimetric (TG) and differential thermal analysis (DTA) was performed on starting mixtures on Netzsch STA 409c equipment, at 10 °C min −1 heating rate in air atmosphere up to 1450 °C. To understand the sintering behavior, thermomechanical analysis on vertical prismatic sample (20.0 × 3.5 × 3.5 mm 3 ) was also performed, with a 5 °C min −1 heating rate in air atmosphere up to 1450 °C (TMA Rigaku Evo plus II, Japan); this has been recently carried out for ceramic based composites [21][22][23].…”

Al2O3–Ce:YAG composite phosphor ceramics for white laser lighting: Novel preparation and regulatable properties

“…Above phenomena indicate that as the excess of Al 3+ increases, the multiphase powder deviates from the normal stoichiometric ratio of Y 3 Al 5 O 12 to a higher degree and the Y 3 Al 5 O 12 phase has a tendency to develop toward YAlO 3 phase. These may be attributed to the more energy for atomic diffusion of Y 3+ to synthetize a mixture of Y 3 Al 5 O 12 phase than to synthetize a mixture of YAlO 3 phase 35. There are some Al 2 O 3 or other aluminum oxide compounds produced at the same time.Figure 3d shows the XRD patterns of the 20-70 wt.% Al 2 O 3 -(Y 0.999 Ce 0.001 ) 3 Al 5 O 12 CPCs vacuum sintered at 1775 • C for 10 h, featuring Y 3 Al 5 O 12 (PDF 33-0400) and Al 2 O 3 (PDF 83-2080) phases.…”