Synchronously enhanced electromagnetic wave absorption and heat conductance capabilities of flower-like porous γ-Al2O3@Ni@C composites

Abstract

Efficient multifunction materials with strong electromagnetic wave (EMW) absorption and high thermal conductance play a pivotal role in addressing the heat accumulation and EM interference problems in miniaturized and integrated electronics. However, incompatibility between EMW absorption and heat conductance makes their simultaneous improvement a major challenging issue. In this work, flower-like porous γ-Al2O3@Ni@C composites are successfully formulated via a hydrothermal-soaking-calcining route. The original findings of the concerted improvement in EMW absorption and heat conductance are reported. By controlling [Ni2+] and sintering temperature (Ts), the interfaces, components, and defects are modified to achieve synergistic enhancement in the performance of the target composites. Results show that the γ-Al2O3@Ni@C composites formed at [Ni2+] = 2.0 M and Ts = 700 °C present an optimal thermal conductance of 2.84 W/(m⋅K) at a low filling ratio of 30 % due to the phonon/electron relay transmiss on in the 3D network of unique flower-like porous structures, clearly superior to γ-Al2O3 and most of the other γ-Al2O3-based composites. Meanwhile, the composites synchronously present a broad absorption band (4.24 GHz, beyond 90 % damping over 15.75 ∼ 18.00 GHz) and strong absorption (-42.43 dB) relative to a 1.7 mm-thick specimen owing to the enhanced damping coefficient and EM parameters. The outstanding properties exhibited by the flower-like porous γ-Al2O3@Ni@C composites suggest that they have promising prospects for application in EMW absorption and thermal management.