Rapid sintering of YAG:Ce-Al2O3 composite ceramic phosphors in minutes for high-power white LEDs/LDs

YAG:Ce-Al 2 O 3 composite ceramics were prepared by the Joule-heating sintering at 1850 °C within 3 min. • YAG:0.012Ce-8Al 2 O 3 ceramic shows relative density of 99.62% and transmittance of 42.3% at 600 nm. • YAG:0.012Ce-8Al 2 O 3 ceramic shows bright yellow-green emission with quantum efficiency of 80.12%. • The assembled white LED achieves a LE of 138.5 lm∙W ‐1 , and white LD delivers a LF of 392.3 lm. YAG:Ce-Al 2 O 3 composite ceramic phosphors are promising all-inorganic color converters for high-power white LEDs/LDs, but the conventional preparation requires prolonged high-temperature sintering. In this work, (100 − y )Y 3- x Al 5 O 12 : x Ce 3+ - y Al 2 O 3 (YAG: x Ce- y Al 2 O 3 , 0.002 ≤ x  ≤ 0.024, 0 ≤ y  ≤ 12 wt%) composite ceramic phosphors were prepared by graphite-assisted Joule-heating sintering. Dense ceramics were obtained at a nominal mold temperature of 1850 °C within 3 min. The effects of Ce 3+ concentration and Al 2 O 3 content on phase composition, microstructure, optical transmittance, luminescence behavior and thermal stability were investigated in detail. The optimized YAG:0.012Ce-8Al 2 O 3 ceramic exhibited a relative density of 99.62%, an in-line transmittance of 42.3% at 600 nm (0.5 mm thickness), an internal quantum efficiency of 80.12%, and a retained emission intensity of 84.26% at 150 °C. The introduction of Al 2 O 3 refined YAG:Ce grains and enhanced excitation-light scattering, thereby improving excitation-light absorption and emission output. The 0.4 mm-thick ceramic-based white LED device achieved a luminous efficacy of 138.5 lm∙W ‐1 , while the 1.2 mm-thick ceramic delivered a luminous flux of 392.3 lm under 450 nm laser excitation. These results indicate that the Joule-heating sintering provides a rapid-processing route for ceramic phosphors toward white LED/LD applications.