In order to study the effect of surface coating time on electromagnetic properties and microwave absorbing properties

carbonyl iron was coated with SiO

2

by hydrolysis of tetraethyl orthosilicate (TEOS). The elements and chemical bonds of the samples were characterized by XRF and FT–IR

and the surface morphology of the samples was analyzed by TEM to determine the thickness of the coating. The electromagnetic parameters were measured by a vector network analyzer to study its absorbing properties. The results show that the surface coating thickness is about 40–60nm. With the coating time prolonged

the thickness of the coating layer gradually increases. After simulation

the absorption peak of the electromagnetic wave after coating is moved to a high frequen

cy

band width (R

L

≤–10dB) increases significantly. The sample coated for 2h has the smallest reflection loss

the lowest peak value is – 45.18dB

which shows good absorbing performance.