Alnico-based hard magnetic particle and method for manufacturing the same
AssigneeKorea Minting, Security Printing & Idcard Operating Corp.
InventorsSoo Dong Kim, Won Kyun Choe, Sung Hyun Joo, Hong Keon Kim, Hyun Soo Kim
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Abstract
Disclosed is an AlNiCo-based hard magnetic particle containing Al, Ni, Co, Cu, Ti, and the balance of Fe. The AlNiCo-based hard magnetic particle contains Co in an amount of 10 to 17 wt %, has a coercive force of 250-450 Oe, and has a residual magnetization/coercive force rate of 0.06 or more. The AlNiCo-based hard magnetic particle according to the present invention can advantageously guarantee magnetic properties suitable for being detected by a magnetic reluctance device due to a low content of Co.
Claims7
A magnetic particle comprising:
- an AlNiCo-based hard magnetic particle disposed at an inside of the magnetic particle and comprising Al, Ni, Co, Cu, and Ti, with a remainder of the AlNiCo-based hard magnetic particle being Fe,
- wherein the AlNiCo-based hard magnetic particle has a Co content between 10% by weight to 17% by weight, a Ni content is between 18% by weight and 25% by weight, an Al content is between 4% by weight and 9% by weight, a Cu content is between 1% by weight and 4% by weight, and a Ti content is between 2% by weight and 5.5% by weight and has a coercive force between 250 Oe and 450 Oe and a residual magnetization/coercive force ratio of 0.06 or more, and
- wherein a sum of a Co content and a Ni content is a value between 32% by weight and 40% by weight.
Security ink comprising a light-color magnetic particle comprising:
- an AlNiCo-based hard magnetic particle disposed at an inside of the magnetic particle and comprising:
- Al, Ni, Co, Cu, and Ti, with a remainder of the AlNiCo-based hard magnetic particle being Fe,
- wherein the AlNiCo-based hard magnetic particle has a Co content between 10% by weight to 17% by weight, a Ni content is between 18% by weight and 25% by weight, an Al content is between 4% by weight and 9% by weight, a Cu content is between 1% by weight and 4% by weight, and a Ti content is between 2% by weight and 5.5% by weight, and has a coercive force between 250 Oe and 450 Oe and a residual magnetization/coercive force ratio of 0.06 or more, and
- wherein a sum of a Co content and a Ni content is a value between 32% by weight and 40% by weight.
A method of manufacturing magnetic particles including AlNiCo-based hard magnetic particles, wherein each of the AlNiCo-based hard magnetic particles is disposed at an inside of a corresponding magnetic particle of the magnetic particles and comprises Al, Ni, Co, Cu, and Ti, with a remainder of each of the AlNiCo-based hard magnetic particles being Fe, the method comprising:
- producing a molten metal by melting an AlNiCo alloy raw material;
- producing minute particles from the molten metal by atomizing the molten metal;
- selecting particles having a predetermined size or smaller from among the produced minute particles through air current classification;
- and
- heat-treating the selected particles in an inert gas atmosphere to form the AlNiCo-based hard magnetic particles,
- wherein the AlNiCo alloy raw material comprises, by weight, from 4% to 9% of Al, from 18% to 25% of Ni, from 10% to 17% of Co, from 1% to 4% of Cu, and from 2% to 5.5% of Ti, and
- wherein a sum of the Co and Ni in the AlNiCo alloy raw material is, by weight, from 32% to 40%.
Dependencies are inferred from the claim text.