Hematite particles and magnetic recording medium having a non-magnetic under-coat layer containing hematite (Fe.sub.2 O.sub.3) particles.
US5750250A · kind A · utility
21Cited by
4References
20Claims
0Family size
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Key dates
| Filing date | Oct 18, 1996 |
| Grant date | May 12, 1998 |
| Priority date | — |
| Expiry date | Oct 18, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2991
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Hematite particles for a non-magnetic undercoat layer for a magnetic recording medium, comprise: high-density acicular hematite particles having an average major axial diameter of not more than 0.3 .mu.m, a major axial diameter distribution in geometrical standard of not more than 1.50 and a BET specific surface area of not less than 35 m.sup.2 /g, showing a pH of not less than 8, and containing not more than 300 ppm of soluble sodium salt, calculated as Na, and not more than 150 ppm of soluble sulfate, calculated as SO.sub.4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.