A Highly Deficient Medium-Entropy Perovskite Ceramic for Electromagnetic Interference Shielding under Harsh...

Area of Science:

• Materials Science
• Aerospace Engineering
• Ceramics

Background:

• Reliable electromagnetic interference (EMI) shielding materials are critical for aerospace applications, especially in high-temperature, oxidative environments.
• Existing conductor-type materials (e.g., metals) degrade under oxidation, while dielectric-type materials lack sufficient shielding efficiency at gigahertz (GHz) frequencies.

Purpose of the Study:

• To develop and demonstrate an efficient EMI shielding material capable of withstanding harsh aerospace conditions.
• To investigate the potential of a highly deficient medium-entropy (ME) perovskite ceramic for high-temperature EMI shielding.

Main Methods:

• Fabrication of a highly deficient medium-entropy (ME) perovskite ceramic.
• Investigated the synergistic effects of entropy stabilization and aliovalent substitution on A-site to create Ti and O vacancies.
• Evaluated the material's stability under high-temperature oxidation (1000 °C in air for 100 h) and its EMI shielding effectiveness in the X-band.

Main Results:

• The ME perovskite ceramic exhibits an abnormally high concentration of stable Ti and O vacancies due to entropy stabilization and aliovalent substitution.
• Vacancy clustering leads to giant complex permittivity and polarization loss in the GHz range.
• Achieved specific EMI shielding effectiveness above 30 dB/mm in the X-band, even after prolonged high-temperature annealing.

Conclusions:

• The aliovalent ME perovskite ceramic demonstrates exceptional EMI shielding performance in harsh environments, outperforming conventional materials.
• Its stability at high temperatures and oxidative conditions makes it suitable for demanding aerospace applications.
• The material's bifunctional properties, including low thermal conductivity, position it for use in aircraft engines and reusable rockets.