To study the relationship between hydrophobicity properties and micro characteristics of composite insulators

four composite insulators operated in Jiangxi power grid were randomly selected for hydrophobicity and hydrophobicity migration tests. Fourier transform infrared spectroscopy（FTIR）

X-ray photoelectron spectroscopy（XPS） and X-ray diffraction（XRD） were adopted to analyze the changes of element content

chemical state

and microstructure. Results show that

due to the increase of surface roughness

serious chalking insulator commonly possesses a big static contact angle.Thus

the static contact angle cannot be used as a sole criterion for evaluating hydrophobicity of a rough surface. Nevertheless

it should be evaluated by the combination of whether there are sufficient hydrophobic groups in the surface.Whether the hydrophobicity migration performance of a composite insulator is high or not is quite consistent with whether there is asiloxane XRD diffraction peak in the surface layer. It is suggested that to detect siloxane XRD peak in the surface layer is a possible method to determine whether the hydrophobicity transfer performance can meet the requirements of continuous operation.