Microwave absorption efficiency of poly (vinyl-butyral)/Ultra-thin nickel coated fly ash cenosphere composite

Abstract

The demand for light weight broadband microwave absorber is ever increasing for defence and civilian applications. A hollow microsphere filler based polymer composite system was studied in the present work owing to its attractive microwave absorbing characteristics. Poly (vinyl-butyral) (PVB) is chosen as the matrix and flyash cenosphere (FAC) is used as filler (hollow microsphere). FAC, being dielectric, is coated with Ni-P using electroless coating method to synthesize core-shell filler(magneto-dielectric). The dielectrics and microwave absorption study was carried out for the frequency range 8.2-18 GHz (X-band and Ku-Band). The minimum reflection loss (RL) was obtained to be −69 dB (thickness 1.5 mm) for~665 nm Ni coated FAC-PVB composite. Further, this composite has excellent microwave absorption efficiency (70 dB GHz/mm). Hence, an ultra-thin Ni coated FAC loaded PVB composite is a potential candidate for broad band microwave absorption.