Precursor-Derived Mo₂C/SiC Composites with a Two-Dimensional Sheet Structure for Electromagnetic Wave Absorption

Area of Science:

• Materials Science
• Ceramic Engineering
• Microwave Engineering

Background:

• Precursor-derived silicon carbide (SiC) ceramics are effective microwave absorbers but suffer from residual carbon issues at high temperatures.
• Applications in harsh environments like high-speed aircraft are limited by carbon content.

Purpose of the Study:

• To develop a novel molybdenum carbide/silicon carbide (Mo2C/SiC) microwave-absorbing ceramic.
• To address the limitations of residual carbon in SiC ceramics for high-temperature applications.
• To enhance microwave absorption properties through a unique 2D sheet structure.

Main Methods:

• Pyrolysis of polycarbosilane-coated molybdenum sulfide (PCS@MoS2) to form Mo2C/SiC composites.
• Controlled reaction between MoS2 and free carbon during pyrolysis to reduce carbon content and form Mo2C.
• Utilizing the layered structure of MoS2 to create a 2D composite architecture.

Main Results:

• Mo2C/SiC ceramics were successfully synthesized with reduced carbon content.
• A two-dimensional composite structure was achieved, significantly enhancing microwave absorption.
• Minimum reflection loss (RLmin) of -46.49 dB at 8.96 GHz with a thickness of 2.6 mm was recorded.
• Effective absorption bandwidth (EAB) covered the entire X-band (8-12 GHz).

Conclusions:

• The novel Mo2C/SiC ceramic effectively mitigates residual carbon issues in SiC absorbers.
• The 2D sheet structure derived from MoS2 significantly boosts microwave absorption performance.
• This material shows great promise for high-temperature microwave absorption applications.