A thin dielectric ceramic coating with good absorbing properties composed by tungsten carbide and alumina

The development of radar absorbing materials (RAMs) with strong absorption is of crucial significance in every aspect of field mobile communication, especially in military, where serious electromagnetic (EM) interference always occurs. However, the application of RAMs has been limited by their thickness. In our study, a novel EM wave absorber, tungsten carbide (WC) and Alumina (Al2O3) composite coating, was prepared using an atmospheric plasma-spraying technology for the first time. The phase structure and microstructure of the coatings were studied with scanning electron microscope and X-ray diffraction analyzer. Their EM parameters were also tested in the X-band (8.2–12.4 GHz) with a microwave network analyzer, and then their EM absorbing properties were calculated through transmission line theory. The results showed that compared with other RAMs, these coatings are thinner and possess good performance in x-band. The absorbing bandwidth for reflection loss (RL) below −10dB can reach 1.5 GHz and 2.2 GHz with the thickness of only 1.1 mm and 1.5 mm, respectively. •Firstly, tungsten carbide and aluminum oxide are common coating materials respectively, and we prepared the composite coating including tungsten carbide and aluminum oxide for the first time.•Secondly, tungsten carbide and aluminum oxide are used as electromagnetic absorber without precedent, which broadens the application range of tungsten carbide.•Thirdly, the dielectric and electromagnetic properties of the composite coatings have been studied in detail for the first time.•Finally, compared with other absorbing coatings, our coatings are thinner and possess good performance in x-band. The absorbing bandwidth below −10dB reaches 1.5 GHz and 2.2 GHz with the thickness is only 1.1 mm and 1.5 mm, respectively. Meanwhile, the absorbing bandwidth below −5dB covers the entire x band with the thickness is only 1.5 mm.