The asphaltene coating effect on GMI response in Fe 4.3Co 68.2Si 12.5B 15 amorphous microwires

Abstract

The asphaltene was extracted from asphalt cement with penetration grade 60, which is extracted from crude Libya petroleum. The asphalt cement was taken from Tupra Refinery in Izmit-Turkey. The asphalt cement was dissolved in 10 times excess volume of benzene, precipitated in a further 10 times excess volume of petroleum ether with a boiling range of 40-60 degrees C (i.e., 1 part asphalt cement, 10 parts benzene, and 100 parts petroleum ether). The resultant precipitate was collected by filtration and dried. The asphaltene so obtained was dark brown semi-solids. The percentage of asphaltene in the asphalt cement was 30% by weight. Fe4.3Co68.2Si12.5B15 amorphous microwires, with a diameter of 120 m and 12 cm long, were coated with these paramagnetic asphaltene molecules. The giant magneto-impedance effect was experimentally measured on uncoated and asphaltene coated Co-rich amorphous wires. In the asphaltene coated sample, a very high value of the giant magneto-impedance effect ratio up to 42% was achieved at 4.0 MHz. As far as is known, such a giant magneto-impedance enhancement is reported for the first time by an asphaltene coating process.