Epoxy resin materials are widely used in HV equipments because of their excellent properties inelectronic

mechanics

heat and other fields. However

under HVDC

the surface of epoxy resin is easy toaccumulate charge

which will distort the electric field nearby and cause flashover. In this paper

micro SiO

2

/EP

nano SiO

2

/EP and nano TiO

2

/EP coating were respectively coated on the surface of epoxy matrix.The DC flashovervoltage of coated samples was measured at 0.1 MPa in air and SF

6

respectively

and flashover voltage of samples afterpreset voltage was also measured at 0.1 MPa SF

6

. The results show that

flashover voltage in the air of coated epoxyresin samples was not quite different from the samples without coating. However

there was great difference amongthem in SF

6

. Among samples containing micron SiO

2

the short-time flashover voltage of 3 wt% was the highest. Boththe short-term flashover voltage of nano SiO

2

and nano TiO

2

coating samples reached their maximum when the contentof particles was 1 wt%. After preset voltage

the flashover voltage of the matrix decreased by 16.7%. For samples containing coating

the flashover voltage was higher than their short-term voltage and greater than the uncoatedepoxy matrix. All the samples with micron SiO

2

/EP

nano SiO

2

/EP and nano TiO

2

/EP coating reached their maximumwhen the particle content is 3 wt%

and the sample with micron SiO

2

particles was highest among them.