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US 11,694,827 B2Granted
Light-colored magnetic particles having improved durability and chemical resistance
AssigneeKorea Minting, Security Printing & ID Card Operating Corp.
InventorsHong Keon Kim, Won Gyun Choe, Su Dong Kim, Hyun Soo Kim, E Den Kim, Hye Jun Choi, Ju Hee Kang
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Abstract
The present invention can provide light-colored magnetic particles having a zirconium oxide coating layer formed on a magnetic core, and having a silver coating layer formed on the zirconium oxide coating layer, and a part of the surface of the zirconium oxide coating layer is exposed to the outside, but chemical resistance is excellent, and thus the magnetic particles hardly cause a change of magnetic characteristics so as to be suitable for security elements.
Claims5
A magnetic particle consisting of:
- a magnetic core;
- a zirconium oxide coating layer formed on the magnetic core;
- and
- a silver coating layer formed on the zirconium oxide coating layer,
- wherein the silver coating layer has a silver content of 10 to 20% by weight relative to a weight of the magnetic core,
- wherein the magnetic core includes one or more selected from the group consisting of Fe, Cu, Al, Ni, Co, Nb, Nd, Si, B, Cr, and Sm,
- wherein the magnetic particle has a reflectance of 50 to 70% at a wavelength of 900 nm, and
- wherein the zirconium oxide coating layer of the magnetic particle is not completely coated with the silver coating layer of the magnetic particle, and a part of a surface of the zirconium oxide coating layer of the magnetic particle is an outside of the magnetic particle.
5 more elements
Dependencies are inferred from the claim text.