Effect on dielectric properties of LDPE due to addition of different structure of BiFeO3 powders

Lamellar and spherical BiFeO
₃
powders were synthesized by the hydrothermal route. The morphology feature of BiFeO
₃
powders was shown using scanning electron microscope. The SEM images of the lamellar BiFeO
₃
powders shows the lamellar size was 1-2 μm and thickness was about 100 nm. Each crystal structure were formed of multilayer aggregate. The images of the spherical BiFeO
₃
powders shows uniform feature with approximately 2 μm in size. Dielectric BiFeO
₃
/LDPE composite with doping lamellar and spherical BiFeO
₃
powders of different percentages including 0.2, 0.5, 1 and 2 wt%, have been successfully prepared by melt blending route. In this work, we studies AC breakdown strength and dielectric spectrum of BiFeO
₃
/LDPE composite. The AC breakdown strength of LDPE was increased due to addition of lamellar and spherical BiFeO
₃
powders of 0.2, 0.5, 1 and 2 wt%. The AC breakdown strength of BiFeO
₃
/LDPE firstly increased and then decreased with the increasing of BiFeO
₃
content. The AC breakdown strength of lamellar-BiFeO
₃
/LDPE composite is higher than of spherical-BiFeO
₃
/LDPE. The dielectric property of BiFeO
₃
/LDPE composite was investigated. The relative permittivity of BiFeO
₃
/LDPE composite is greater than LDPE and firstly decreased then increased with the increasing of doping BiFeO
₃
content. The relative permittivity of lamellar-BiFeO
₃
/LDPE composite is smaller than the spherica-BiFeO
₃
/LDPE composite under the same conditions.