Fabrication, Microstructure, and Optical Properties of Eu:Gd _0.6 Lu _1.3 O ₃ Transparent Ceramics From Co‐Precipitated Powders

ABSTRACT Eu:(Gd,Lu) 2 O 3 transparent ceramics show exceptional promise for high‐energy X‐ray imaging due to their superior radiation resistance and high light yield. To overcome challenges in achieving high optical quality and optimized luminescence performance, this study establishes a synergistic calcination‐sintering process: 5 at.% Eu:Gd 0.6 Lu 1.3 O 3 nanopowders synthesized via co‐precipitation were calcined at 1050°C–1300°C for 4 h, followed by vacuum pre‐sintering at 1600°C for 4 h, hot isostatic pressing (HIP) posttreatment at 1700°C for 3 h under 200 MPa Ar, and annealing at different temperature (1100°C–1500°C). It is demonstrated that the calcination temperature critically exerts a critical influence on powder morphology and crystallinity, directly governing the final optical quality of ceramics. Crucially, 5 at.% Eu:Gd 0.6 Lu 1.3 O 3 ceramics from 1100°C‐calcined powders exhibit optimal microstructure with uniform grains (16.1 µm) and pore‐free grain boundaries. This optimized microstructure endows the ceramics with excellent optical transparency, achieving an in‐line transmittance of 79.8% at 800 nm and 78.2% at 611 nm (the characteristic emission peak of Eu 3 + ). The X‐ray excited luminescence (XEL) intensity peaks at 1400°C annealing, reaching approximately 10 times that of a Bi 12 GeO 20 (BGO) crystal, but declines at higher temperatures due to scattering‐induced light loss. Thermoluminescence analysis confirms progressive trap elimination with increasing annealing temperature. In addition, XEL spectra reveal intense emission, with a light yield about 10 times higher than that of Bi 12 GeO 20 (BGO) single crystal, and a decay lifetime of 0.96 ms. These findings establish that both precise control of calcination temperature and optimized annealing temperature are essential for producing high‐performance Eu:(Gd,Lu) 2 O 3 transparent ceramics for advanced scintillation applications.