Patent ID: 6547889
Filing Date: 2003-04-15
Classification: G11B,Y10T

Abstract:
An iron-based alloy sheet as a sheet material having a thickness in the range from 0.1 mm to 5.0 mm for use as a material of a magnetic yoke to build up a magnetic circuit in a hard-disk voice-coil motor which is formed from an iron-based alloy consisting essentially of inherent side elements as follows:from 0.0001 to 0.02% by weight of carbon; from 0.0001 to 0.05% by weight of silicon; from 0.001 to 0.2% by weight of manganese; from 0.0001 to 0.05% by weight of phosphorus; from 0.0001 to 0.05% by weight of sulfur; from 0.0001 to 0.1% by weight of aluminum; from 0.001 to 0.1% by weight of oxygen; and from 0.0001 to 0.03% by weight of nitrogen, and from 0.1 to 10% by weight of cobalt as an adjuvant element, the balance to 100% by weight being iron and unavoidable impurity elements, and which exhibits magnetic parameters including:a saturated magnetic flux density in the range from 2.07 to 2.3 Tesla; a maximum magnetic permeability in the range from 1000 to 20000; and a coercive force in the range from 10 to 400 A/m.