Effects of graphite additive on dielectric properties and microwave absorption properties of zinc-containing foam glass

This paper reports effects of graphite additive on dielectric properties and microwave absorption performances of zinc-containing foam glasses. Changes of pore structure of porous glass are analyzed. One-dimensional zinc oxide crystal whiskers on walls of foam glass are observed. With the graphite additive increases, both real (ε′) and imaginary (ε″) parts of complex permittivity increase from ~ 3.25 and ~ 0.2 to ~ 7.5 and ~ 2.8, respectively. Microwave reflection loss of porous glass was calculated based on the permittivity in the range of 8.2–12.4 GHz(X-band). Reflection loss of foam glass decreases as graphite additive and the sample with 2.0 wt% graphite additive achieve reflection loss less than − 10 dB in whole X-band with thickness ranging from 2.3 to 3.5 mm. Linear relation between reduction of reflectivity and increase of graphite content is achieved. The results show that changing foaming agent additive is an efficient way to design dielectric and microwave absorption properties of foam glass. Foam glass with 1.0 wt% graphite additive may find application in photocatalytic degradation of many environmental pollutants due to its considerable zinc oxide whiskers.