58 / 2022-03-08 14:55:03

Ferromagnetic Quantum Dots Improving Dielectric Properties of Polypropylene Film in Strong Electromagnetic Field

film capacitors,Polypropylene,Electromagnetic Field,Dielectric Properties,conductivity,dielectric constant,breakdown strength.

Purpose/Aim

Polypropylene (PP) dielectric capacitors is an ideal energy storage device for electromagnetic launch power supply system. However, the insulation reliability of PP film decreases significantly in strong magnetic field. Therefore, it is of significance to improve the dielectric properties of PP film in the strong electromagnetic environment.

Experimental/Modeling methods

0.005 wt% ~ 0.5 wt% 20 nm Fe₃O₄ particles were introduced into the PP dielectric films. The dielectric constant, leakage conductivity and breakdown strength of the pristine and modified samples were investigated under 0, 4, 8, and 12 T magnetic field. The insulation performance degradation mechanism of PP under electromagnetic environment was proposed. The quantum chemical calculation (QCC) was applied to analyze the charge trapping effect of Fe₃O₄ nanoparticles.

Results/discussion

With the enhancement of the magnetic field from 0 to 12 T, the dielectric constant declined by 0.07 at 1 kHz, the conductivity increased to 230 %, and the breakdown strength was improved by 24 % at 12 T.

Conclusions

The magnetic field inhibited the polarization and excited electrons, resulting in the insulation deterioration. The Fe₃O₄ particles can capture the high energy carriers and improve the film performance.