1：Experimental Design and Method Selection:

The study uses the nitrate pyrogenation method for synthesizing Y2O3 nanopowders and a hybrid sintering method combining low-temperature presintering and hot isostatic pressing (HIP) for fabricating transparent ceramics. This approach is chosen to achieve fine-grained ceramics without sintering additives to maintain high thermal conductivity.

2：Sample Selection and Data Sources:

Y(NO3)3·6H2O (99.99% purity) is used as the raw material. Deionized water is used to form solutions. Samples are characterized using various techniques to analyze properties.

3：99% purity) is used as the raw material. Deionized water is used to form solutions. Samples are characterized using various techniques to analyze properties. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes a muffle furnace, ball mill, zirconia jars and balls, cold isostatic press, hot isostatic press, annealing furnace, polishing equipment, TG-DTA, XRD, TEM, SEM, BET apparatus, UV/VIS/NIR spectrophotometer, FTIR spectrometer, universal material testing machine, Vickers hardness tester, and laser flash apparatus. Materials include Y(NO3)3·6H2O, deionized water, anhydrous ethanol, zirconia balls, and argon gas.

4：Experimental Procedures and Operational Workflow:

Y2O3 nanopowders are synthesized by dissolving Y(NO3)3·6H2O in water, heating to form a gel, and thermally decomposing at 600°C. Powders are ball-milled for 48 hours, dried, sieved, pressed into disks, cold isostatic pressed, presintered at temperatures from 1300°C to 1450°C, HIP-treated at 1350°C under argon, annealed, and polished. Characterization involves TG-DTA, XRD, TEM, SEM, BET, transmittance measurements, mechanical testing, and thermal conductivity measurements.

5：Data Analysis Methods:

Data are analyzed using software like Nano Measurer for grain size distribution. Statistical methods include averaging values from multiple samples for mechanical tests. Thermal conductivity is measured using the laser pulse method.