Microwave absorbing ceramic coatings with multi-walled carbon nanotubes and ceramic powder by polymer pyrolysis route

Abstract

Glass powder, talcum powder and multi-walled carbon nanotubes (MWCNTs) filled silicone resins were prepared for microwave absorbing coatings which can be used at elevated temperature. The impact strength and adhesive power, complex permittivity and reflection loss of the coatings at room temperature and after heat treatment were studied. Both the adhesive power and impact strength of the coatings can be adjusted by the glass powder content, and enhanced after heat treatment. The real part (ε′) of permittivity of the coatings decreased slightly while the imaginary part (ε″) kept almost constant after heat treatment. The reflection loss values below −10 dB can be obtained in the frequency range of 12.7–18 GHz at room temperature and 12.4–15.6 GHz at 600 °C for the coating after heat treatment. These results indicated such coatings containing glass powder, talcum powder and MWCNTs can be a promising microwave absorbing ceramic coating with both good mechanical properties and microwave absorption.