ACTA

Breakdown Driven by Magnetic Field in Gradually Aged Ferrofluid

J. Kurimský^a, M. Rajňák^{a, b}, R. Cimbala^a, I. Kolcunová^a, B. Dolník^a, J. Džmura^a, J. Petráš^a, J. Zbojovský^a, P. Bartko^a, M. Ivančák^a, M. Timko^b, P. Kopčanský^b
^aTechnical University of Košice, Letná 9, 041 54 Košice, Slovakia
^bInstitute of Experimental Physics SAS, Watsonova 47, 040 01 Košice, Slovakia

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This study deals with a specific problem of the impact of magnetic field on the breakdown voltage in gradually aged ferrofluid. The examination was conducted on the samples containing a certain volume of mineral oil with several volume concentrations of iron oxide superparamagnetic nanoscaled particles with surface modified by oleic acid. It is known that certain concentrations of particles in dielectrical insulating oil can improve its electrical withstanding capability. However, the improvement is related to specific operating conditions. In the context of the current research we report a more complex study where the external magnetic field was applied in breakdown voltage tests conducted with the ferrofluid thermally aged for three consecutive 200 h aging periods. The test fixture was designed for the experimental purpose. During the observation, the DC low-level external magnetic field was applied. The interaction of dispersed particles with external electric and magnetic field resulted in a change of the expected breakdown voltages. We present the breakdown voltage variations depending on two-parameters: the thermal aging and application of external magnetic field. The measurements are analyzed statistically. The ability of the particles to act as space charge accumulators at each stage of the experiment is proven.

DOI:10.12693/APhysPolA.137.939
topics: magnetic fluid, dielectric breakdown, magnetic field