15 декабря, 2015 
Pokraskin Pigments with a coercive field strength of 50-57 kA m-1 are used in videocassettes, high-biasaudiocassettes (chromium dioxide operating pointlEC II),andhigh-density floppy disks. Depending on the quality of the tape, the particle size varies between 0.2 and 0.4 pm (see Section 5.1.1, Table 5.1, and Figure 5.1).
Pigments with a higher coercive field strength (ca. 70 kA m-1) and smaller particle size (particle length ca. 0.15-0.2 pm) are used for super VHS cassettes.
Pigments treated with only small amounts of cobalt (0.5-1 wt.% Co, coercive field strength ca. 31 kA m-1) are used as an alternative to cobalt-free y-Fe2O3 pigments
for high-quality low-bias audiocassettes. The other parameters described in Section
5.1.1 are also of importance for cobalt-treated pigments.
Cobalt-containing pigments are mainly produced by the magnetic iron oxide producers Toda Kogyo, Titan Kogyo (Japan), 3M, Magnox (USA), Saehan Media (South Korea). World production in 2002 was about 25,000 t, of which the highest amount (ca. 85%) was used for videotapes.
5.1.3
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