Mechanically robust Al₂O_3 f/LaPO₄/Al₂O₃ composite for high-performance microwave transparent

Al₂O_{3 f}/Al₂O₃ composites are considered the up-and-coming candidates for high-temperature microwave transparency applications due to their low dielectric constant, and excellent resilience to heat and oxidation. The interface phase plays a critical role in determining the mechanical properties. Here, the LaPO₄ interface layer was introduced in the Al₂O_{3 f}/Al₂O₃ composites successfully via a straightforward and effective precursor transmission method. The fabricated Al₂O_{3 f}/LaPO₄/Al₂O₃ possesses a low porosity of 13.5 % and a high density of 2.61 g/cm³. As anticipated., its bending strength reaches 110.3 MPa and its fracture displacement reaches 0.21 mm. More important, the microwave transmittance remains above 90 % for thicknesses ranging from 1 to 2.28 mm and 7.25–7.77 mm throughout the X-band (4.2 GHz, 8.2–12.4 GHz). Consequently, they create prospects for utilizing interface strategies to design a category of functional materials that possess both high strength and high-temperature microwave transparency for various applications.