Coaxial electrospinning fabrication and radar-infrared compatible stealth properties of Zn0.96Co0.04O nanotubes

Wurtzite-type Zn0.96Co0.04O nanotubes are prepared through coaxial electrospinning technology and heat-treatment for 2 h at 600, 700 and 800 °C. The phases, morphology, microwave absorption properties and infrared emissivity are investigated by TGA, XRD, SEM, TEM, vector network analyzer and a IR-2 infrared emissivity tester respectively. The results show that pure wurtzite-type Zn0.96Co0.04O is formed at 600 °C and above. As the heat-treatment temperature increas, Zn0.96Co0.04O exhibit the morphology of hollow tubes, short nanotubes and irregular nanoparticles. Dielectric loss is the main loss mechanism of Zn0.96Co0.04O nanotubes. The matching thickness of Zn0.96Co0.04O nanotubes is 2 mm, at which the microwave absorption properties are fine. The minimum reflectivity is −20.3 dB at 9.5 GHz, and the effective absorption frequency band less than −10 dB is 8.4–12.0 GHz, with the bandwidth of 3.6 GHz. The average infrared emissivity value of Zn0.96Co0.04O nanotubes is 0.72.