Piezoelectric ceramics and dielectric polymers have been extensively studied for energy storage (capacitor) and data storage applications. Polymer dielectrics are used because of their high dielectric breakdown strength but they have low relative permittivity values. On the other hand, ceramic dielectric materials have higher dielectric values but suffer from lower breakdown field strength and tend to overheat, which results high energy loss and lower energy conversion efficiency. Dielectric composites that incorporate a high permittivity material (usually a ceramic) in a matrix with high breakdown field strength (typically a polymer) are of interest where opportunities of leveraging both characteristics is ideal. Different types of composites have been made using barium titanate, barium-strontium titanate, and aluminum particles with polymer matrices. However, the high dielectric materials are typically inorganic compounds that do not exhibit good adhesion with the organic matrix, resulting in inconsistent dielectric properties over large frequency ranges and leaching over thecycle life of the device or as a function of high concentration of active filler. Recently, researchers have turned towards core-shell processing techniques that result in an organic chain coating that enhances the interaction between the inorganic and organic phases of the composite. In this work, the materials of interest were surface treated aluminum–epoxy composites. The dielectric composite solution was spin coated onto stainless steel sheets and were corona polarized at 45 kV/mm under a constant temperature of 75C. The capacitance and dissipation spectra (2 kHz to 20 MHz) were captured to understand the dielectric properties of the devices. Hysteresis loops were observed to determine the dielectric breakdown of the material and to characterize the appropriateness for application as capacitor materials.

Investigation of novel coatings for aluminum particles for composite dielectric materials

255th National Meeting (2018)

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