Complex characterisation of Cr-doped α-Al 2O3 for DBD applications

Abstract

Al2O3 samples doped with Cr2O3 up to 10vol.%(12.7wt%) were investigated with respect to their electrical, structural and morphological properties relevant to their use as a dielectric barrier in dielectric barrier discharges (DBDs). The surface properties were analysed using atomic force microscopy and a scanning electron microscope. The structural properties were investigated using x-ray diffraction (XRD) analysis. Regarding electrical properties, we measured the dielectric constant of the material, the discharge ignition voltage in a coplanar configuration in the air as well as in nitrogen, and the working domains (WDs) of atmospheric pressure Townsend discharge (APTD). The charge-trapping properties of the studied samples were measured by an electrostatic voltmeter. There was observed a significant ignition voltage decrease with maximal decrease for sample doped with 1vol.%Cr2O3 . For the samples doped with 10vol.% of Cr2O3 a rapid surface potential decay was observed that is important from the viewpoint of DBDs plasma filamentation due to the so-called surface memory effect. The WDs of the APTD showed variations, and it has been significantly extended for the 5Cr sample up to at least 24 kHz compared to other samples. Thus, the results presented in this paper show the potential of Cr-doped dielectric barriers and point towards future research directions.