Study On Fabrication Of Amorphous Soft Magnetic Ribbons Used In Magneto-acoustic Marker

Recently, acoustic magnetic electronic article surveillance(EAS) system is one of the best surveillance systems, and has widely been applied. The magneto-acoustic marker is key part for the acoustic magnetic EAS system. The marker demand amount has intensely increased. Up to now, fabrication technology of the 58 kHz surveillance system has been monopolized by Sensormatic Company. It is still blank field in domestic. It’s significant to develop fabrication technology of the magneto-acoustic marker. In this work, resonator of magneto-acoustic marker has been investigated. It’s expected to find a suitable method to produce eligible magneto-acoustic marker, and also to enrich theoretical foundation.In this work, the amorphous ribbon was fabricated with single-roller melt-spinning technique. The effect of technological parameter on the microstructure of amorphous ribbon was studied. Relation among fabrication technology, ribbons morphology and ribbons structures were investigated. Some of main results are as follows:(1)Three component amorphous ribbons were fabricated with single-roller melt-spinning technique. The results shows that thickness of ribbons decrease with increasing rotation rate, increase with increasing distance between nozzle and copper roller, and increase with increasing nitrogen injection pressure.18～28 μm thickness amorphous ribbons were fabricated through controlling the above craft parameters.(2)The fabrication technology is very important to structure of amorphous ribbons. The ribbon is amorphous structure with high rotation rate, and becomes crystallization with low reducing rate. In small distance between nozzle and copper roller, the ribbon is amorphous structure. At low nitrogen injection pressure, the ribbon is amorphous structure.(3)The amorphous ribbons were produced into resonator marker. The acousto-magnetic property was investigated. The results show that the resonant frequency is in the commercial application range (58 kHz). The acousto-magnetic property of amorphous ribbons is increased obviously after annealing treatment. The annealing treatment can improve the acousto-magnetic property, but the perpendicular magnetic annealing show the best performance.(4)The reasonable fabrication route is that firstly ribbons with amorphous structure are produced, and than the ribbons are annealed under perpendicular magnetic field. The ribbon (component of Fe25.8Co12Ni57.6Si0.81B3.79) with amorphous structure (fabricated in r=1800 rpm、h=0.1 mm、P=0.05 MPa) performs the best response distance (48 mm) after 340℃,8 min perpendicular magnetic annealing.