To investigate the relation between nano-particles dispersion and the dielectric properties of AlO3/silicone rubber composite

two methods were adopted to prepare composites with nano-AlO3 loading of 1%

2%

3% and 4% respectively.The first method is to mix nano-AlO3 powders and silicone rubber by homogenizer（named method 1）

and the second one is to disperse nano-AlO3 powders in liquid

then mix the dispersion liquid with silicone rubber（named method 2）.The transmission electron microscope（TEM） was used to observe the dispersion of nano-particles in the composites.It can be seen that in the samples prepared by method 2

nano-AlO3 dispersed well.Dielectric properties of space charge

dielectric spectroscopy and conduction current were test.The results show that good dispersion of nano-AlO3 in the silicone rubber could decrease the accumulations of space charge

increase carrier mobility

decrease permittivity and conduction current density and increase the electrical aging threshold of the composites.It was concluded that the dispersion of nano-AlO3 impacts on the dielectric properties of silicone rubber composites.