Changes in the Surface Morphology, Microhardness, and Physicochemical Properties of Natural Minerals under the Influence of a Dielectric Barrier Discharge

Effect of High-Voltage Nanosecond Pulses and Dielectric Barrier Discharges on the Structural State and Physicochemical Properties of Ilmenite Surfaces

“…Our studies were performed out using the procedures in [15][16][17][18][19][20] and individual grains of ilmenite (Fe,Mg)TiO 3 from a sample of stream sediment (Juina, Brazil) and specially prepared polished sections ~4.5 mm thick. The grains of ilmenite were 1-4 mm in size, opaque, black with a metallic luster, semiangular, and irregularly shaped with a flinty fracture.…”

“…The conditions of exposing the ilmenite samples to the effect of nanosecond electromagnetic pulses (HPEMPs) and radiation from the low-temperature nonequilibrium plasma (LTP) of a dielectric barrier discharge (DBD) in air under standard conditions were described in [15][16][17][18][19][20], along with the electrophysical parameters of the high-voltage pulse generators. The duration of sample treatment varied in the range t treat = 10-150 s. With the HPEMP effect, the duration of high-voltage nanosecond pulses was 4-10 ns.…”

“…Pulse amplitude U ~ 25-30 kV; strength of the electric field in the 5 mm interelectrode gap, E ~ 10 7 V m −1 ; rate of nanosecond pulse repetition f = 100 Hz. Electrode voltage in the cell of the barrier discharge generator, 20 kV; pulse duration, 8 μs; duration of a pulse leading edge, ~300 ns; rate of pulse repetition, 16 kHz; length of interelectrode gap, ~5 mm [15,[17][18][19].…”

“…The load on the indenter was 100 g, and the period of loading was 10-15 s. The streaming (flow) potential (ζ-potential, mV) of mineral particles (size ≤50 μm) was determined using a Microtrac ZETA-Check Zeta Potential Analyzer. The contact angle of wetting (Θ°) of polished sections of the surfaces before and after energy treatment was measured with sessile drops of distilled water ("resting" on the surface) ~2-3 mm in diameter, following the procedure in [15,17,18]. Analysis was done using a digital optical microscope and the ImageJ program with special DropSnake and LB-ADSA plug-ins [22].…”

“…The aim of this work was to study and comparatively analyze the impact of two types of nonequilibrium electrical discharges (high-power electromagnetic pulse (HPEMP [13]) and dielectric barrier [14,15] discharges in air at atmospheric pressure) have on the morphology, structural state, microhardness, and electrical and physicochemical surface properties of ilmenite from rocks of the Juina district of Brazil.…”