| 摘要 |
PROBLEM TO BE SOLVED: To make taking-out difficult and to permit the prevention of forgery by providing an information recording medium with a base material consisting of a nonmagnetic material and alloy fibers which are embedded into this base material and have specific sizes and high magnetic permeability. SOLUTION: The alloy fibers to be embedded into the base material are preferably formed to >=1 to <500 μm in width, >=0.1 to <=200 mm in length and >=1 to <20 μm in sheet thickness. The alloy fibers are produced by an apparatus having the constitution consisting of a rotatable cooling roll 3 and a nozzle 2 for injection for introducing a molten alloy from an alloy supply section disposed on this cooling roll 3. After the base alloy is melted, this molten alloy is injected onto the cooling roll 3 rotating in the direction of an arrow c from the nozzle 2 for injection and is ultrarapidly cooled, by which the alloy is transported toward an arrow d and the alloy fibers 1 are obtained. The cooling roll 3 is composed of, for example, an iron alloy or copper alloy and the molten metal injection port at the front end of the nozzle 2 for injection is formed to a rectangular shape. |
