Acousto-magnetic anti-theft label with a high coercivity bias and method of manufacture
US8746580B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 18, 2012 |
| Grant date | Jun 10, 2014 |
| Priority date | — |
| Expiry date | Oct 13, 2032 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22C1/02
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high coercivity bias piece for making acousto-magnetic labels is made of an alloy strip with 10-14% weight percent Mn, less than 7% weight percent of one or more other transitional metals, with the balance Fe, after cold rolling to final gage, going through a final aging heat treatment at below 590 C, longer than 5 minutes. The strip thickness is 0.065-0.18 mm with coercivity measured by direct current method being 56-90 Oe. The method of making the high coercivity bias piece is to cold roll the strip to 0.07-0.15 mm with aging temperature at 450-570 C, for 0.5-20 hours to form a magnetic strip with coercivity of 60-85 Oe, followed by cutting the strip to required size. This high coercivity bias piece is manufactured without expensive Co and Ni materials, showing that a low cost Fe-(10-14% weight percent Mn) based alloy can be used to make high coercivity bias.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.