| 摘要 |
PURPOSE: To obtain a magnetic card, a manufacturing method thereof and a manufacturing method of a magnetic powder using the same which enables recording of novel information easily and the preventing of the forging thereof. CONSTITUTION: A magnetic layer of a magnetic card has a coercive force of 5.0kOe or more and is made of a magnetic powder with a magnetization exceeding 25% in saturation magnetization by an applied magnetic field half as much as the coercive force at the most. The magnetic powder is as given by a formula of R×T100- X (wherein R represents a rare earth element containing at least one kind of Y having Sm as main component and T at least one kind of transition metal having Co as main component with 16.0<=x<=22.0at%). This facilitates recording on the magnetic layer but makes hard or impossible to do the erasing and reloading of the information recorded. In the manufacturing of the magnetic powder used for the magnetic layer, an alloy comprising one kind of an ingot, a sintered body and a mixture of the sintered body and an RD powder as given by the above formula is crushed and further undergoes a thermal treatment at 750-1,200 deg.C under vacuum or an inert atmosphere to produce. |
