Microwave

Quantum mechanics

Composite number

Engineering

Boron

Pyrolysis

Materials science

Boron nitride

Coating

Pyrolytic carbon

Layer (electronics)

Carbon fibers

Chemical engineering

Physics

Nanotechnology

Organic chemistry

X-ray photoelectron spectroscopy

Composite material

Analytical Chemistry (journal)

Chemistry

Scanning electron microscope

Fourier transform infrared spectroscopy

Nitride

Boric acid

Applied Surface Science

Boron nitride coatings were synthesized on pyrolytic carbon (BN-coated PyC) particles via chemical reaction of boric acid and urea in nitrogen. The results of Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FI-IR) and X-ray photoelectron spectroscopy (XPS) show the formation of boron nitride coating. The TGA curves indicate that the oxidation resistance of the PyC particles is improved by incorporating BN coating on the surface. The mass of the BN-coated PyC particles remains over 60% at 1200 °C whereas the PyC particles are oxidized completely at 920 °C. The investigation of microwave absorbing property reveals that compared with the PyC particles, the BN-coated PyC particles have lower permittivity (ɛ′, ɛ″) and better absorbing property. The BN-coated PyC particles show a strong absorbing peak at 10.64 GHz, where the lowest reflectivity −21.72 dB is reached. And the reflectivity less than −10 dB is over the range of 9.6–12 GHz.

Preparation and study on microwave absorbing materials of boron nitride coated pyrolytic carbon particles