Surface engineering of nanoflower-like MoS2 decorated porous Si3N4 ceramics for electromagnetic wave absorption

Abstract

MoS₂ is a typical two-dimensional material that has attracted considerable attention in the field of electromagnetic wave absorption because of its high specific surface area and excellent electrical and semiconductor properties. The fabrication of ceramic matrix composites with MoS₂ as the absorbing phase remains a significant challenge given the high temperature sensitivity of MoS₂. Herein, we demonstrate a simple, efficient, and scalable surface engineering method for achieving in situ growth of nanoflower-like MoS₂ within the pores of porous Si₃N₄ ceramic by a combination of vacuum infiltration and hydrothermal reaction, which avoids the traditional high-temperature co-sintering process of MoS₂ powders and Si₃N₄ powders. The MoS₂ nanoflowers were anchored to the rod-like Si₃N₄ without significant detachment and agglomeration, which was attributed to the formation of Mo–N bonds. The prepared nanoflower-like MoS₂ decorated porous Si₃N₄ ceramics exhibited excellent microwave absorption performance, and the effective absorption bandwidth completely covered the X-band (8.2–12.4 GHz) in the thickness range of 3.36–3.70 mm. The minimum reflection loss was −68.66 dB at a thickness of 3.06 mm. The excellent electromagnetic wave absorption performance was attributed to the strong polarization loss, which in turn was attributed to the combination of the rich surface structure, the defects of the MoS₂ nanoflowers, and the abundant heterogeneous interface between MoS₂ and Si₃N₄. The findings of this work provide novel insights for developing composite ceramics with highly temperature sensitive materials as the wave-absorbing phase.