Enhanced Electromagnetic Wave Absorption for Y₂O₃-Doped SiBCN Ceramics.

Area of Science:

• Materials Science
• Ceramics Engineering
• Nanotechnology

Background:

• Polymer-derived SiBCN ceramics (PDCs-SiBCN) are advanced ultrahigh-temperature ceramics.
• They possess notable high-temperature oxidation resistance and electromagnetic wave (EMW)-absorbing capabilities.
• Optimizing their microstructure is key to enhancing these properties.

Purpose of the Study:

• To investigate the impact of Y2O3 doping on the microstructure, dielectric, and EMW absorption properties of SiBCN ceramics.
• To understand the role of Y2O3 as a catalyst in forming crystalline phases.
• To evaluate the high-temperature oxidation resistance of the doped ceramics.

Main Methods:

• Synthesis of Y2O3-doped SiBCN ceramics.
• Microstructural analysis to observe phase evolution.
• Dielectric property measurements.
• Electromagnetic wave absorption performance testing.
• High-temperature oxidation resistance evaluation up to 1500 °C in air.

Main Results:

• Y2O3 doping promoted the formation of SiC, BN(C), and graphite crystalline phases.
• These crystalline phases act as conduction and polarization centers, significantly enhancing EMW absorption.
• Achieved a minimum reflection loss (RLmin) of -42.22 dB at 15.28 GHz.
• Obtained an effective absorption bandwidth of 4.72 GHz (13.28-18.00 GHz).
• Demonstrated excellent oxidation resistance with only 0.56 wt % mass loss after heating to 1500 °C in air.

Conclusions:

• Y2O3 acts as a catalyst, promoting crystalline phase growth and improving EMW absorption and oxidation resistance in PDCs-SiBCN.
• The study presents a novel strategy for microstructure regulation and property enhancement of polymer-derived ceramics.
• These findings offer a promising method for developing advanced ultrahigh-temperature ceramics with superior performance.