1：Experimental Design and Method Selection:

The study used solid-state reactive sintering to prepare translucent Al2O3-Ce:GdYAG composite ceramics with varying Al2O3 contents and thicknesses. The method was chosen to achieve uniform dispersion of Al2O3 particles in the Ce:GdYAG matrix for improved thermal and optical properties.

2：Sample Selection and Data Sources:

Commercial raw materials including α-Al2O3, Y2O3, Gd2O3, and CeO2 were used. Samples were prepared with molar ratios of Al2O3/Ce:GdYAG of 0,

3：5, 6, 7, and 8, and thicknesses from 4 mm to 1 mm. List of Experimental Equipment and Materials:

Equipment included a planetary ball mill (QM-3SP2, Nanjing Chi Shun Technology Development Co., Ltd), X-ray diffraction system (XRD, Model D/max2200 PC, Rigaku, Japan), high-resolution field-emission scanning electron microscope (FESEM, S-4800, Hitachi, Japan), fluorescence spectrophotometer (F-4600, Hitachi, Japan), laser pulse apparatus for thermal diffusivity, high temperature specific heat meter (MHTC96, Setaram, France), and a high accuracy array spectroradiometer with an integrating sphere (HASS-2000, Hangzhou, China). Materials included α-Al2O3 (

4：99%, Fenghe Ceramic Co., Ltd), Y2O3 (999%, Fujian Changting Golden Dragon Co., Ltd), Gd2O3 (999%, Jining Zhongkai New Materials Co., Ltd), CeO2 (99%, Alfa Aesar Co., Ltd), tetraethyl orthosilicate (TEOS), and MgO as sintering aids. Experimental Procedures and Operational Workflow:

Raw materials were mixed via ball milling, dried, calcined, pressed into green bodies, and sintered under vacuum. Sintered samples were polished, annealed for thermal etching, and characterized using XRD, SEM, PL/PLE measurements, thermal diffusivity, specific heat, density measurements, and optical property testing with blue LED packaging.

5：Data Analysis Methods:

Thermal conductivity was calculated using κ = α·Cp·ρ. Optical properties such as luminous flux, efficacy, CRI, and CCT were analyzed from spectroradiometer data.