Porous ZrO 2 –ZrO 2 ceramics with excellent mechanical strength and permeability for transpiration cooling

Abstract The great development of transpiration cooling technology challenges the coolant medium seriously. In this paper, porous ZrO 2 –ZrO 2 ceramics have been satisfactorily prepared to meet the requirements of the coolant medium in transpiration cooling. The results illustrate that porous ZrO 2 –ZrO 2 ceramics have excellent compressive strengths; meanwhile, percentages of compressive strength difference (parallel and perpendicular to the mold‐pressing direction) have an upward trend due to the increasing fiber contents. Besides, the failure mode has a huge distinction between parallelity (45° oblique section) and perpendicularity (wedge shape). These ceramics have unimodal pore size distribution (2–10 µm), and their wettability has a substantial improvement reflected by contact angle from 118° to 0°. Permeability behavior across these ceramics has been accurately described using the Darcy–Forchheimer equation, while obtaining viscous and inertial resistance coefficients, respectively. This work can provide an essential reference for coolant medium in transpiration cooling.