Improving comprehensive properties of Ca-α-SiAlON ceramics via Yb³⁺doping for radome application

α-SiAlON ceramics, owing to their unique crystal structure and tunable properties, are considered ideal candidates for next-generation high-performance wave-transmitting materials for radome applications. However, α-SiAlON ceramics exhibit a high dielectric constant, and optimizing both their wave-transmitting properties and mechanical performance at elevated temperatures remains a significant challenge, limiting their application in wave-transmitting fields. In this work, a high-temperature solid-state method was used to synthesize Yb³⁺and Ca²⁺co-doped α-SiAlON ceramics, and the influence of Yb³⁺doping on the microstructure and properties was systematically analyzed. The results show that, within the X-band (8.2-12.4 GHz), the ceramics exhibit a real dielectric constant ranging from 8.44 to 8.58, with wave transmission exceeding 70 % for thicknesses up to 0.71 mm. Additionally, the ceramics demonstrate room-temperature thermal conductivity of 4.17 W/(m·K) and a flexural strength of 479.3 ± 12.6 MPa. Compared with Ca-α-SiAlON, the Yb/Ca-α-SiAlON ceramics show enhanced thermal-insulation capability and improved mechanical properties while maintaining excellent wave-transmission performance. This work presents a viable strategy for the synergistic optimization of thermal insulation, wave transmission, and mechanical properties in α-SiAlON ceramics.